Kneeguards
From AmtWiki
Catchers shinguards (popularly called Mechs) are often used for leg protection because they provide protection for both the knees and shins. Some example pictures are [image:Macgregor-b61-double-knee-baseball-catcher-varstiy-leg-guard.jpg|200px].
You can often buy these used at used sporting good stores such as Play it Again Sports