I am frankly surprised that an extension jack equipped with a potentiometer for volume (and not limited to Apple products) is so hard to find today. But this one did not disappoint me. The potentiometer works perfectly (I have read other reviews indicating a change in low volume, but for me, the volume varies without levels of total silence to 100% power), the jack contacts are francs and firm without being hard, the whole is light and compact (no need to clip or other media to support the potentiometer), and I could perceive no loss of sound quality. Just 2 minor complaints and a question mark: - The potentiometer can be adjusted by sliding a knob of about 2 cm on a zone of perhaps 3cm. Basically, it was 1 cm to go from 0 to 100%, so it's not always easy to adjust its volume accurately. - 1.20 meters cord, I find it too long. As for me, 75 cm would have been enough, and I doubt that many users may need more than 1 m. Why do that too long wire? All we win, it is the increased risk of pinched or hang it somewhere. - The thread is very fine and gives an impression of fragility. This is not really a criticism because I sometimes saw son much stronger for some thicker son (the thickness of the rubber sheath can not guarantee the quality of the wire), but I ask myself right Similarly, the question of the lifetime.