"Add more dogs to your high performance SportDOG Brand WetlandHunter 425X Dog Training System with the WetlandHunter 425X Add-A-Dog Collar. Durable collar includes a compact receiver with a range of up to 500 yards. Receiver unit delivers up to 21 levels of static stimulation at a medium or high intensity, tone, and vibration corrections. Patented DRYTEK technology provides waterproof protection up to 25' under the water. Comes with rechargeable lithium-ion battery with quick-charge (2 hours) design. Battery offers 4060 hours of use per charge. For dogs 8 lbs. and up with neck sizes 5""22"". Add-a-dog collar includes: receiver on 3/4"" camo collar, charging adaptor, long contact points, and operating guide. Add-on collar for WetlandHunter 425X Dog Training System 500-yard range Offers tone, vibration, and up to 21 static stimulation levels Medium or high stimulation intensity DryTek waterproof design submersible to 25' Rechargeable lithium-ion battery in collar For dogs 8 lbs. and up with neck sizes 5""22"""