You can't have too much protection.
Constructed from a stretch Kevlar material, the Alpinestars MTB Knee Sock is designed to be used in conjunction with knee pads as an extra line of defense against injury. The sock provides additional muscle and soft tissue support for folks with bad knees or those who are prone to coming down hard on their knees. Elastic mesh at the back of the knee cools things down, and elastic edges with silicone grippers keep the knees socks in place.
Alpinestars MTB Knee Socks come in three sizes: XS/S, M/L, and XL/2XL, and in the color Black.