Sliding Door Upper Guide Block 80-90. 251-843-423 251843423 Was £8.95 - Now £8.06! Quantity: at £8.06 each Add To Basket Sliding door upper guide block. This is the Nylon guide block that slides in the roof channel as you open and close the sliding door. Fits all Type 25/T3 80-90. Fits left or right side Top quality part made in Germany.