【Extremely Durable】This collar is highly durable and will not easily wear or tear. It can withstand even excessive, active dog training and control. 【Slidable Stop Ring】The slidable O-ring is difficult to move to adjust to the perfect size, but this is necessary to prevent it from easily moving when the collar is in use. 【Martingale Collar】This collar can be used as a Martingale collar to correct bad behavior or for training. This collar helps prevent pulling, but it does not choke the dog's neck. It can be tightened by pulling when necessary, but it remains sufficiently loose. ✳︎ Thickness 8mm, Length 45cm ✳︎ Opened for inspection, but unused.