Battery life varies between the two (3 / 12 Hours vs 40 Hours), which affects how long you can use them on a single charge. There is a noticeable difference in weight (45 Gm vs 20 GM), which may affect comfort during extended use. boAt Airdopes 138 and Unix UX-999 PRO 2 are well-known options in the wireless headphone segment, offering a balance of audio quality, battery performance, and smart features. Overall, both headphones are feature-rich and cater to users looking for a combination of sound quality, comfort, and wireless convenience. Impedance levels vary (NA vs 32 Ohms), which can affect compatibility and audio output when used with different devices. The frequency response differs (20 Hz - 20000 Hz vs 20Hz - 20KHz), which can influence how well the headphones reproduce lows, mids, and highs. Both headphones are equipped with capable drivers that deliver balanced sound output suitable for music, calls, and entertainment. boAt Airdopes 138 uses Bluetooth 5.0+EDR while Unix UX-999 PRO 2 supports Bluetooth 5.1, which can impact connectivity stability and efficiency. Both models feature noise cancellation, helping reduce background noise for a more immersive listening experience.

Verdict: Both models are competitive, and your decision should be based on your usage needs and preferred features.