When measuring your current collar, please measure the length of the inner diameter that matches the size of the collar. Toy Poodle, 10.9 lbs (4.9 kg), S size, Schnauzer, 10 months, 6 kg), S size, Corgi, 25.3 lbs (11.5 kg), M size, Golden Retriever 88.2 lbs (40 kg), L size.