Caninestar 550 yards Remote Dog Teach & Training Collar - 8 Levels Static Shock & Vibration & Beep - Rechargeable, Waterproof, Durable with Anti-Interference Design for Both Indoor & Outdoor Use Eight levels of static stimulation plus 1 level of vibration correction mode and sound warning mode Around 550 yards range outdoors with built-in anti-interference technology for indoor use as well Rechargeable, 100% Waterproof (collar only) and Durable Patented ergonomic collar design incorporates flexible metal prongs to reduce pressure on skin surface Train up to 3 dogs simultaneously using a single handheld remote