1999 Hendrickson MT20A, Truck Delivery, Tag Axles, Fits to: Mack RD688S, (Used) 1999 Mack RD688S, TAG AXLE- Make: Hendrickson, Model: MT20A-A57A, Serial Number: 6003784, For more information about this item, give us a call. We ship Worldwide! (CRG HEAVY TRUCK PARTS) 929 W PULASKI HWY ELKTON, MD 21921, Serial# 6003784, Casting# 6003784, Truck Year 1999 1M2P267C0XM043425