Small: up to 15 lbs, 9-13″ neck
Medium: 15-60 lb, 13-19″ neck
Large: 60-105lb, 19-24″ neck
To find the correct collar size: Wrap a piece of string loosely around your pets neck. Mark the string where it overlaps to form a complete circle. Measure the length to the mark, which is the minimum size required.
Washing Instructions: Remove batteries. Secure battery housing screw. Soak in a mild soap and water mixture. Open battery housing and allow to air dry. Replace batteries once unit is completely dry.