The Boombot REX is a ultraportable, ruggedized, water-resistant, rechargeable speaker and hands-free for smartphones but most of the above… it punches enough bass out of the small box with inbuilt subwoofer to shake some real stuff. The USB rechargeable lithium-ion batteries last longer than any portable speaker in this price – with up-to 6 hours of backup time. Integrated with iPhone Siri, it’s the perfect companion in your adventurous expeditions. So many features, so much convenient..