The X-Mini II is capable of playing decent-sounding music for up to 11 hours on a single charge. You can use it with your phone, MP3 player, phone or MP4 player with a 3.5mm speaker. Sophos have given me ten of the gadgets to give away to you! All you need to do is take our survey on cyberwarfare and if you’re lucky youll be one of the names pulled out of the hat for an X-mini II.”]
Source: https://grahamcluley.com/win-xmini-ii-portable-speaker-sophos-survey/