The one I get at class is a nylon choke but without a snap on it. I start class at 6 months but have used my choke working with younger pups at home for obedience and show handling. If used properly and high up on the neck to prevent choking it will not do any damage.
: Amazon.com: Coastal Pet Products DCP330218BLK Round Choke Collar for Dogs, 3/8 by 18-Inch, Black