
Flat collar, medium length lead that is thin enough so you can shorten it around your hand if you want to.
No lead, collar etc will stop your dog from pulling though. To do THAT, train him off lead to walk to heel, and reward him every few steps for being next to you.
Progress to doing it on a loose lead in the ssame place and then go to pavements etc.
You CAN use someting that prevents him from pulling, for the times you CANT be training, but if you use those exclusively (headcollars, harnesses etc), they wont ever teach him not to pull.
Em