American Standard Reliant Plus Bath Shower Pressure Balance Cartridge (Blister Pack 100) - AMS-77171

It's the pressure balance cartridge, the internal repair part that keeps shower outlet temperature steady when someone flushes a toilet or runs a washer on the same supply. When a Reliant Plus tub/shower valve starts running hot or cold with no handle movement, or dribbles at the spout, this cartridge is the piece that gets swapped, not the whole valve body. It's an American Standard repair part, part number 077171-0070A.

Bulk. The AMS-77171 is a blister pack of 100 cartridges, which is how a property manager or MRO stockroom buys it when a whole property is on Reliant Plus valves. If you only need one or two for a single repair, this is the wrong pack size to order.

No finish applies. The cartridge sits inside the valve body behind the escutcheon, so it ships unfinished, and trim finish is chosen separately at the escutcheon and handle. Nothing about this part changes the look of the shower.

Single-lever tub/shower valves are exactly where a pressure balance cartridge lives, and it's the usual repair when the shower loses temperature stability or the handle gets stiff. The 077171-0070A is the Reliant Plus version of that part. If your valve instead has a separate temperature limit dial and a thermostatic body, that's a different cartridge type and this one won't serve.

Yes, on a standard pressure balance valve the cartridge comes out from the front once the handle, escutcheon and retaining clip are off, so the wall stays closed. Shut the supply first and check the stops behind the escutcheon. The cartridge itself is a drop-in repair part, not a valve body replacement.