Collar sizes:
XS 20-29cm x 1.5cm wide
S 29 - 40cm x 2.5cm wide
M 36-52cm x 2.5cm wide
L 42-64cm x 2.5cm wide
Martingales:
Whippet 26-36cm x 4cm wide
Greyhound 33-46cm x 4cm wide
How to adjust martingale
Adjust slider to fit - there should be no slack
Tags can snag & catch - attach them
the twin slides should never touch
You should fit 3 fingers between slides when taut