S:15-18",total length is 20"(51cm), 5 holes adjustable
M:17-20",total length is 22"(56cm), 5 holes adjustable
L:19-22",total length is 24"(61cm), 5 holes adjustable
you should be able to get 2 fingers width between the collar
CHORMED D-RING FOR LEAD ATTACHING - A heavy duty D-ring which studded by for mushroom reviets plated for leash attachment,sturdy enough for walking or training dogs

• S:15-18",total length is 20"(51cm), 5 holes adjustable
• M:17-20",total length is 22"(56cm), 5 holes adjustable
• L:19-22",total length is 24"(61cm), 5 holes adjustable
• you should be able to get 2 fingers width between the collar
• CHORMED D-RING FOR LEAD ATTACHING - A heavy duty D-ring which studded by for mushroom reviets plated for leash attachment,sturdy enough for walking or training dogs

S:15-18",total length is 20"(51cm), 5 holes adjustableNeal LINK