Aetertek 400 Yard Remote 1-Dog Training Shock Collar for Small, Medium Dog 400 YARD REMOTE CONTROL RANGE; RECHARAGEABLE SMALL AND LIGHTWEIGHT REMOTE; 10 LEVELS OF ADJUSTABLE BEEP,VIBRATE,SHOCK; RECHARGEABLE,WATER-RESISTANT(NOT WATERPROOF) RECEIVER; Light weight(1.1oz/30g), small(5.5cmx3cmx1.3cm); CAN BE UPGRADED TO 2-DOG TRAINER