Premier Gentle Leader Quick Release Head Collar Medium Royal Straps are made of supple nylon Wont chokepressure is applied at the back of the neck vs. the front of the throat. For dogs 25 - 60 lbs Can be used with dogs eight (8) weeks of age or older. Comes with easy-to-follow fitting instructions, an abbreviated training guide, and a more comprehensive training DVD. A 66-pg. training booklet is also available.