Fits smaller breeds 15-50 lbs. measuring 9.5" to 14" neck circumference. Weighs just 7.5 oz. Now with Collar Sleep Mode to save the battery life. Rechargeable Li-Ion battery, 3/4 " red collar strap, 18 1/2 " standard antenna, charge clip, AC adapter, vehicle power cord, contact point set (long and short) w/ wrench. Manual.