ADD ON ITEM ONLY - MUST BUY COLLAR WITH PURCHASE 
 
HIGHLY recommend only purchasing this with regular buckle collars... but I can add it to martingales. The issue with adding to martingales is that it may slightly impend the way a martingale collar works. 
 
Add this to your cart with the purchase of another collar to have elastic straps sewn to the inside of your collar to hold a seresto collar. These are sewn into the collar based on the neck measurement you provide, so make sure it's accurate in your collar order!