This is a set of four horn valves that includes a stop ("Stopf") valve. Unknown brand or age. Condition is as shown. All valves and slides move. Brace on main tuning slide unsoldered on one side. One valve is missing a bearing plate and another valve has a mismatched bearing plate. One linkage arm is also missing the screw to fasten string on the backside. (Note: "Stopf" switch valve does have bearing plate, but I removed it for the photo. It is included!)Bore seems to be 12mm. Please let me know if I can provide additional photos or information. I am not a horn player so I am sure some of my verbiage is off. Thanks for looking!