When ribbed v-belt performance matters, the MATRIX PRO MX4PK850 delivers — built to the same dimensional and material standards as the original part it replaces. The part is built to the following specification: Length [mm]: 850, 0 mm, Weight [kg]: 0, 065 kg, Number of ribs: Copper. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. This part supersedes original equipment references: 04-00845-SX, 04-00853-SX, 04839, 050 004 0850 and 159 more. Matching these numbers confirms a like-for-like replacement with no loss of function. MATRIX PRO is a recognised supplier of automotive engine timing components to independent workshops and dealer networks across Europe. All parts are sourced from authorised distribution channels and carry full manufacturer traceability — you receive exactly the same component supplied to professional garages and dealer workshops. If fitment or specifications do not match your vehicle, our technical team can help identify the correct alternative — use the vehicle selector or contact us with your VIN for a guaranteed-fit recommendation. Replacing worn components on schedule preserves your vehicle's safety, reliability, and resale value — and aftermarket parts from established brands deliver OEM-equivalent performance at a fraction of the dealer price. Every part is dispatched from our UK warehouse with a 30-day money-back guarantee and free hassle-free returns.