The Moentrol Pressure-Balancing Volume-Control 3-Function Transfer Valve with Stops features the M-PACT common valve system and integral check stops. Changing the look of your bathroom has never been faster and easier. The M-PACT Common Valve System allows you to upgrade the trim style or swap out finishes on your fixtures without replacing the valves. So once the system is in place, you can change your decor as often as you want at any point in time -- during construction process or years down the road. All it takes is a few minutes. Best of all, the M-PACT Common Valve System is as easy to install as a standard valve.