Scuba Pro Mk 16 first stage piston. Packaging is a little sad but the part has been protected.
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 !