Umpire knee protection?

[voiceoflg]

I was at the Biscuits-Barons AA game in Montgomery Saturday night. It looked like the catcher got crossed up and PU took a pitch to the knee. After a delay the PU got back to work but a couple innings later he was done. The 3BU went behind the plate and the rest of the game was done with two umpires.

My question is what protection do umpires wear for the knees and legs? Obviously no matter what you wear, sometimes the ball just finds skin and bone.

Thanks.