Bringing innovation to the world of CPR training, MCR Medical Supply introduces the most realistic CPR training valve on the market today. The trainers feature an integral air filter and valve that obstruct the flow of contaminants. These valves give your student the most realistic rescue mask training experience possible as they duplicate field-use rescue valves in both form and function. Packaged as 10 valves per box, they do not include a training rescue mask. These valves fit CPR masks with standard universal valve attachment ports. For training purposes only - always remember to replace the mask's original valve and filter assembly after training.