We chose a wire muzzle with rubber cover from @fordogtrainersuk. We found that wire muzzles are resistant to bites after some check (Jett never bit, but we are responsible). We like that there is enough space for air and treats (very important). We also like that Jett can open mouth, which is very important for our dog as he yawns (this helps dogs to regulate body temperature) and he is very active.