Thomson® 500 Series profile rails now come standard with an enhanced carriage design that delivers 66% smoother operation with up to 50% lower drag force than previous models. Additionally, a ball spacer carriage option is available to reduce carriage running noise by up to 6 dB. Enhanced design models are 100% interchangeable with previous Thomson® 500 Series carriages and rails. The new design optimizes the surface interfaces between steel and plastic transition areas along the ball bearing circulation path for more precise operation. New standard end seals provide twice the contaminant protection compared to competitive products, with optional low drag end seals idea for low push-force requirements. Thomson® Ball Carriage, Enhanced, Series: 500, Standard Block, 15 mm W Rail, 47 mm Width, 20.2 mm Height, 56.6 mm Length, 24 mm Slide Height, M4 Bottom/M5 Top Carriage Hole Size, For Use With: 521P15A 1500 mm L Single Piece Profile Rail, 9000 N Dynamic/19600 N Static, 5 m/s Maximum, Steel Carriage, -40 to 80 °C