Monday, September 26, 2022

COSTAR Diamond On T300 Buds Review: Here’s what the New Player has to offer within budget

- Advertisement -

In the Indian audio market, there are multiple big players with all types of targeted audiences. Giants like Sony, Bose target the premium segment consumers, whereas Mivi, boAt, Noise are pledged to fulfil the budget segment consumers’ demand. To make this competition even more challenging, COSTART comes in.

COSTAR has launched its first product recently, which is the COSTAR Diamond On T300. It’s a truly wireless earphone that comes with ANC, transparency mode, game mode, and more. The full package costs Rs.1,699 only and is available via Amazon India and COSTAR’s official website. There are three colour options – Dynamic Black, Smart Grey, and Elite White. As a reader of our publication, you can get an additional 10% discount. Just need to use the TECHNO10 discount code.

I received the Dynamic Black colour variant and in this review, sharing my experience with the COSTAR Diamond On T300 over the past 5 days.

COSTAR Diamond On T300 Buds Review - - 8
  • No gimmick ANC
  • Deep bass
  • Multiple Modes
  • Comfortable fit
  • Easy Control
  • Slightlt heavy audio output



  • The designer team has masterfully used linear, geometric and symmetrical design to reveal a futuristic edge. Costar Diamond Buds has gone through more than 300 iterations. Diamond buds are finally finished with a pearlescent baking process that presents 20 perfect facets
  • The Active Noise Cancellation technology enables you to enjoy audio with minimum distractions
  • With the active Noise Cancellation tech, you can still hear crystal voice clearly in the noisy environment. Voice Assistant compatible with the Google/Siri Assistant
  • Better immersive Audio experience with the PEK Composite Diaphragm Technology 10mm Dynamic Bass Boost Drivers
  • IPX4 Water & Sweat Resistant: Enjoy your workout without worrying about sweat
  • Transparency Mode| ANC Mode| 70ms Ultra Low Latency Game Mode | Standard Mode
COSTAR Diamond On T300 Buds Review - - 14

In the Box:

  • Diamond On T300 Buds
  • Charging Case
  • Type-C cable
  • Extra Ear Tips
  • Paperworks

Design & Build:

Design and build are the first things that attract consumers. And then comes the in-hand feel. The COSTAR Diamond On T300 comes with a nearly diamond-shaped charging case carrying a pair of (obviously) small and lightweight earbuds. Good quality plastic is used for it. For the Dynamic Black variant, the orange interior is very eye-catching. The outside of the charging case and the buds get a matt finish, however, it attracts minor fingerprints. The COSTAR branding is placed on the lid, the Type-C charging port is there at the bottom, and in front, there is a LED indicator for charging.

COSTAR Diamond On T300 Buds Review - - 3

COSTAR crafted the buds with almost the same theme as the charging case. As I already mentioned, the buds are small in size and lightweight as well. Each bud has LED indicator and touch-enabled multi-function buttons. These buds are IPX4 certified which indicates protection from sweat and splashes.

On the hand, the overall unit feels solid and durable, yet light in weight. It weighs around 110 grams only.


- Advertisement -

In this section, COSTAR put a lot of features that any customer can ask for in a TWS. It carries 10mm audio drivers inside, which are responsible for the output. Along with it, there is ANC, Transparency mode, and game mode. Let’s discuss them one by one.

First is the audio output. It is well tuned from all aspects compared to most of the other wireless earphones available under Rs.2,000. The bass is well managed, besides the other audio components. The stereo experience I have experienced while watching any movie was impressive. I have tried tracks, OTT content, and audio stories as well. My verdict for the audio is the same in all cases. It is one of the best debut audio projects I can say within the pocket-friendly market. If you already experienced any high-end earphones, the sound may feel a bit suppressed. I’m completely okay with it and can assure it’s hardly noticeable.

  • COSTAR Diamond On T300 Buds Review - - 10
  • COSTAR Diamond On T300 Buds Review - - 16
  • COSTAR Diamond On T300 Buds Review - - 7

Now time for the Active Noise Cancellation. You may find a few brands offering ANC under Rs.2,000 but hardly can trust. As usual, my expectation was the same in this case also. But COSTAR proves me wrong. On paper, they have used the Comf-ANC algorithm. It claims 91% less noise with it. Though I can’t measure this, the buds reduce 60% to 70% of your surrounding noise for sure, which is truly admirable.

Transparency mode is the feature you will not get at this price, not even on paper. After enabling it, the microphones come into action. It captures your surrounding sounds and delivers them with ongoing media audio. It worked smoothly for me. Coming to Game Mode which brings down the latency to 70ms. As per my observation, there is a noticeable audio shift while enabling this mode. This shift actually improved the audio quality for me and reduces the latency.

Combining all these features related to audio, the experience is exceptionally well for me and capable enough to challenge other leading audio brands.

COSTAR Diamond On T300 Buds Review - - 2

Microphone & Calling:

Other than the audio quality, the microphone and calling experience are also equally important. On top of that, the microphones are directly involved in all the available modes’ functionality. It works properly during the calls; catch and transfer my words properly to the opposite person. All calls went smooth without any interruption and no one asked for any voice drop.


Bluetooth 5.0 is there on board for the connectivity with the support of SBC and AAC audio codec. For the first time, need to pair it with your primary device which takes around 6 seconds in total. It reduced to around 3 seconds from the second time onwards. Only opening the lid is enough to enable Bluetooth and initiate the pairing process.

There are no major latency issues, even in the normal mode. The connection also remains strong most of the time. It got disconnected three times in the beginning of the testing, but get connected again within seconds. However, in the past couple of days, this issue didn’t repeat.

COSTAR Diamond On T300 Buds Review - - 9

Comfort & Usage:

The buds are small in size and lightweight, which I have already mentioned. The design allows these buds to sit perfectly in the ear and I never need to adjust them twice while using. The silicon ear tips provide additional grip. The stick is small in size. So, there is very less chance you miss any tap on the multi-function button.

COSTAR manages to include all the controls with the MFBs including track and call handling, voice assistant, mode changes, and even power off. However, it misses the volume control. I understand it’s difficult to add all when there are three different modes to access. I think the integration of mobile application support can solve this issue where users will be able to enable/disable functionalities as per their needs. In Diamond On T300 Buds, the voice assistant can be used as an alternative to adjusting the volume.

This TWS is fully qualified in the Comfort and Usage section. It maintains overall comfort and beautifully integrates most of the controls into two buttons.

COSTAR Diamond On T300 Buds Review - - 6

Battery life:

The COSTAR Diamond On T300 Buds comes with a promise of 16 hours of total battery life. The buds drain 50% of battery life in two hours with ANC and Game Mode on at a volume of 50%. With the same setup, I got around 6 hours of battery life in total. I’m sure in normal mode and keeping the ANC off the battery will increase at least by an hour. It is enough for a full day of usage.

Fortunately, the company used the Type-C port and not the MicroUSB port. It doesn’t have fast charging technology. So, the quick topup will not happen. The case with the buds takes around 2 hours to get charged fully. The LED indicator in the case shows breathing red while charging and stops blinking when touched 100%.

COSTAR Diamond On T300 Buds Review - - 4


It is very difficult to meet end consumers’ all demands with the debut product and COSTAR almost achieved it with the Diamond On T300 according to me. The ANC is not a gimmick here, the transparency mode works too. It delivers the basics, including enjoyable audio quality across media contents, calling, battery life, and management, very beautifully and that also at aggressive pricing. COSTAR didn’t even compromise in style and design. There are three colour options – Dynamic Black, Smart Grey, and Elite White. For the overall package need to spend only Rs.1,699. It is available via Amazon India.

Purchase Link:

- Advertisement -


Design & Build
Microphone & Calling
Comfort & Usage
Battery life
Anupam Modak
Anupam Modak
A CS Engineer and Tech Enthusiast who likes to fiddle with the latest gadgets and tech happenings around the world.



Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Related Articles

Bitdefender WW

Stay Connected

Ajio [CPS] IN

Hot Topics


Latest Articles



COSTAR Diamond On T300 Buds Review: Here's what the New Player has to offer within budget In the Indian audio market, there are multiple big players with all types of targeted audiences. Giants like Sony, Bose target the premium segment consumers, whereas Mivi, boAt, Noise are pledged to fulfil the budget segment consumers' demand. To make this competition even more...

Adblocker detected! Please consider reading this notice.

We've detected that you are using AdBlock Plus or some other adblocking software which is preventing the page from fully loading.

We don't have any banner, Flash, animation, obnoxious sound, or popup ad. We do not implement these annoying types of ads!

We need money to operate the site, and almost all of it comes from our online advertising.

Please add to your ad blocking whitelist or disable your adblocking software.

%d bloggers like this: