[ADD-ON HEADPHONES FOR ENSEMBLE] The AS50Q is intended as add-on headphones for the Avantree Ensemble TV watching set, batches T24B1 or T24D2 and later. For all other batches, please get the AS50. [EXTENDED PLAYTIME] A battery life of up to 35 hours provides entertainment for days. [LIGHTWEIGHT & COMFORTABLE] Soft, spacious earpads and an adjustable headband ensure all-day comfort. [NO LIP-SYNC DELAYS] When used with the Ensemble transmitter, enjoy perfectly synced visual & audio with less than 40ms of delay – perfect for TV watching. [LONG RANGE] Maintain a stable signal up to 100ft / 30m from the Ensemble transmitter.