Please help identify

The plastic valves inside my shower has started leaking. If I use the shower, it will either not turn off and continue to drip, or leak around the valve. I'm having a hard time finding the replacement piece. Unfortunately I can't find a picture of the valve and that would take turning the water off and pulling it apart currently. But if anyone can help identify the manufacturer and maybe a place to buy parts, it'd be greatly appreciated. I've searched for hours and can't find anything. House was built in 1984 in Florida if that helps.

http://ift.tt/1FJIkyN

http://ift.tt/1FJIkyN

Please help identify