This clamp is a replacement of the typical tie wrap that you use to hold your mouthpiece on to your second stage. This will work on MOST second stages that are a standard size but not every second stage.
Make sure that you get a reputable service technician to service your regulators. Aqua Sport Scuba Center Inc takes no liability or responsibility for the service work done with the sale of any service kits. It's up to you to be a responsible adult and understand your risks and responsibilities. Training and experience is very important. Play safe !