How is the battery life of devil Bluetooth speakers?

An overview of the battery life of devil Bluetooth speakers*: BOOMSTER: up to 18 hours at medium volume BOOMSTER GO: up to 10 hours Fender x devil ROCKSTER AIR 2: up to 58 hours battery life Fender x ROCKSTER CROSS: up to 16 hours battery life Fender x devil ROCKSTER GO 2: up to 28 hours battery life MOTIV® GO: up to 16 hours battery life MOTIV® GO VOICE: up to 16 hours battery life MOTIV® HOME: up to 15 hours battery life MYND: up to 42 hours battery life in Eco mode at medium volume ROCKSTER: up to 20 hours battery life ROCKSTER AIR 2: up to 58 hours battery life ROCKSTER CROSS: up to 16 hours battery life ROCKSTER GO 2: up to 28 hours battery life ROCKSTER NEO: up to 36 hours battery life according to IEC standard *The overview only includes Bluetooth speakers with a built-in rechargeable battery that are currently available for sale.