WD2 offers a 300 series stainless "C" channel rail which securley captures the WD2 sliding block. Our WD2 Blocks are self-lubricating, resist edge loading, low friction (real low in water), FDA/USDA/3A Diary/Washdown Compliance, will not allow media to adhere to it and unlike ball of roller systems, has no mechanical failure modes. Because the WD2 block is designed with a flush channel, washdown fluids and debris are easily evacuated during washdown procedures.