1/2 MILE RANGE: Half mile range static collar that can support training up to 3 dogs with the same remote with purchase of additional collars (SDR-AXF). For dogs 8 pounds or larger with neck sizes 5" - 22". NO LOOK OPERATION: Designed for ease-of-use and no look operation while offering more levels of stimulation which allows for more customized training. 21 LEVELS OF STIMULATION: This electric collar offers 21 levels of static with low/medium ranges. Option to train with vibration (buzz) and tone (beep), too. WATERPROOF: Submersible to 25 feet using DryTek technology. RECHARGEABLE BATTERY: Lithium-ion batteries charge in 2 hours and last 50-70 hours per charge. System has low battery indicators.