Battery life varies between the two (6 Hours vs 10 / 40 Hours), which affects how long you can use them on a single charge. Both headphones are equipped with capable drivers that deliver balanced sound output suitable for music, calls, and entertainment. There is a noticeable difference in weight (NA vs 45 Gm), which may affect comfort during extended use. boAt Rockerz 255R and boAt Immortal 121 are well-known options in the wireless headphone segment, offering a balance of audio quality, battery performance, and smart features. Impedance levels vary (16 ohm vs NA), which can affect compatibility and audio output when used with different devices. Both models provide a wide frequency range, delivering a balanced audio experience across different types of content. boAt Rockerz 255R uses Bluetooth 4.1 while boAt Immortal 121 supports Bluetooth 5.3, which can impact connectivity stability and efficiency. boAt Rockerz 255R and boAt Immortal 121 offer different noise cancellation capabilities (No vs NA), which can impact how effectively they block external noise. From a usability standpoint, both models provide a reliable and premium headphone experience.

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