The walnut cleaning adapter is designed to aid in the removal of carbon buildup on BPY FSI intake valves. The design allows the use of a walnut blaster with little to no mess just attach a vacuum to the other port. The walnut cleaning adapter is a strong, durable printed item that works perfectly and flawlessly every time. The BPY FSI engines are notorious for carbon buildup. This buildup robs your engine of power and efficiency as it reduces airflow to the cylinder. Manual carbon cleaning is time consuming and near impossible to remove all carbon buildup. Walnut blasting drastically speeds up the process and will leave you with cleaner valves! Designed for: BPY 2.0T S4 3.0L Designed to work with a vacuum hose - 25mm Designed to work with blaster - 10mm