Easy to put on - difficult to slip off! * Two Velcro straps with slides fasten the boots in place. * Petite 1 1/4"; X-Small 1 3/4$; Small 2 1/4" width; Medium 2 3/4" width; Large 3 1/4" width * Please review "How to Measure for Ultra Paws Dog Boots" within our store details page within Amazon