Divoom iTour Rock Portable Bass Driven Speaker for Smartphones - Retail Packaging - Green Digital amplifier processor to ensure a clear audio source. "Link-Link" design allows you to connect as many iTour Rock speakers or other Divoom speakers as you like! Best party partner! Built-in rechargeable battery for up to 7 hours of quality playback. Patented PO-bass technology produces a deeper and more powerful bass. Color: Green. Compatible with all iPod, iPhone, iPad, Tablet, Phone, PSP, DS, MP3 Player and other media devices.