These are premade french martingales and cannot be modified. Small dog french martingales are available in XS and S and feature a 3/4" wide collar part and a 1/2" wide leash. The leash is 5'. Regular french martingale is available in sizes XS-XL and feature a 1" layered on 1.5" collar with a 5/8" wide leash. Leash length is 4'. All french martingales come with an O ring on the handle and a keeper on the martingale part.
To size it correctly, your dog's neck size should be slightly larger than the smallest measurement.
