Five calls in one. Overlap/interrupt technology (allows you to instantly change calls without having to wait). Auto shut off (two minutes). Ergonomic design for easy-to-use, one hand push button operation. Convenient belt clip/strap clip. Handy on/off thumb dial for easy volume regulation. Sure-hold rubberized grip. Lightweight. Water resistant design. External speaker/headphone port. Operates on 3 AAA batteries (included).