Aspen Pet Prong Training Collar will be a great help in your training. It is a sar, proactical tool for training while keeping your dog comfortable during training. It is great for walking strong pullers, large dogs, and for obedience training and behavior correction.
Helps control even the most stubborn dog
Uses pressure points around the dogs neck to help leash train
Electronically welded for maximum strength
Nickle and chrome plated for added durability
Great for strong dogs
 
SIZES:
Small/Light Weight: 2.33mm x 14"
Medium: 3.0mm x 18"
Large/Heavy: 3.3mm x 20"
X-Large/X-Heavy: 3.8mm x 22"