When catalyst converter performance matters, the WALKER 20856 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]: 420 mm, Weight [kg]: Ceramic, 000 kg, Code Letter: 91, Supplementary Article/Info 2: 515, Guarantee: Cast Iron. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. Compatible with OPEL, VAUXHALL vehicles; use the vehicle selector above to confirm exact fitment for your make, model, and engine variant. Fitment data is sourced from TecDoc, the authoritative European parts catalogue. This part supersedes original equipment references: 090-157, 090-721, 20856, 21765 and 9 more. Matching these numbers confirms a like-for-like replacement with no loss of function. WALKER is a recognised supplier of automotive replacement 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.

Walker, part of the Tenneco group, is a well-established manufacturer of exhaust system components with decades of engineering experience. Walker specialises in catalytic converters, diesel particulate filters, exhaust pipes, silencers, and flexible connectors. As a supplier meeting strict European emission regulations, Walker products are designed for precise fitment and optimal exhaust gas treatment. With extensive vehicle coverage and products engineered to restore factory exhaust performance, Walker is a dependable choice for exhaust system repairs across all major European vehicle brands.