What the heck are these?

[grannyknot]

A friend of just bought a box of Z items, brake MC, proportioning valves, calipers, etc.  I recognize everything in the box except these 3 little wigets, a spring on one end connected to a hard rubber cylinder with a soft rubber tab at the end.  They look familiar but I'm stumped.

 

[Mark Maras]

????????????????

[jonbill]

They look a little like the seals from inside the master cylinder.

[dutchzcarguy]

Residual pressure valve.. here's one from Jeep...  ?  

 

[grannyknot]

12 hours ago, dutchzcarguy said:

Residual pressure valve.. here's one from Jeep...  ?  

That's why they look familiar,  I have a 2lb residual pressure valve for my rear brakes.