The new RC-8 ULTRA-COLLAR is simply the most advanced radio dog containment collar made. The radio box is Ultra-light, weighing only 1.2 oz., and packed with features not found on any other radio collar. The RC-8 has a built-it stimulus test lamp that let's you test the shock output without having to deal with a cumbersome external test lamp. Operating condition is checked continuously by the collar's internal computer chip. An auto-flashing LED tells you that the collar is fully operational. The RC-8 is fully waterproof and features a tone speaker that transmits sound directly to the outside world. (Other collars transmit sound through the casing.) That means the RC-8 gives you louder training tones for faster boundary training. Add to all that a beautiful, yet nearly indestructible, poly-elastomer strap that is integral with the radio box and you've got THE state-of-the-art electronic collar. Works with ALL Humane Contain Models including: HC-350, HC-7000, HC-7000A, HC-7000B and HC-8000. Also works with RADIO MAT Electronic Scat Pad. Requires one B3V-8 Replaceable Battery.