Suitable for high speed and high cycling applications, DEFENDER 1 Nitride-Plus Linear Rail™ System has hardened steel bearing rails with Nitride-Plus coating for extended life. Rails come in lengths of 40.94, 59.84, 81.89, and 122.83 in. Each 3-bearing roller block or slider unit is 3.15 in. long and available in 300 series stainless steel or zinc plated. Equipped with lubricated for life bearings and ZZ seals, hardened 52100 bearing steel rollers can be washed down.