The Cliff Keen The Impact Adult Knee Pad boasts a patented ergonomic construction and anatomical compression-molded "bubble" which provides high-impact protection, and an excellent fit. The knee pads are sold individually and are one size fits most adults and teenagers. The knee pad provides great protection and a fit that will leave you comfortable and feeling great. Patented ergonomic construction and anatomical compression- molded “bubble” provides high-impact protection and an excellent fit. Machine washable, tumble dry, no heat. One size fits most. Sold individually. Ergonomic Construction. High-Impact Protection.