How to determine the right size for your dog:

LEUCHTIE will be placed over the dog's head as closed ring and turns on and off automatically.

Consequently, for choosing the right size you have to measure the dog's head circumference, not the neck.

Please put a tape measure tightly around the widest part of the dog’s head. Select the LEUCHTIE size closest to this measurement. If you measure between two sizes, please choose the smaller size preferably.