Precision 57.85mm seal for secure boost connections Ensures airtight fit, prevents boost leaks Compatible with multiple VW T5 & Mk4 engines This 57.85mm boost hose O-ring seal is designed to provide a tight, leak-free connection in turbocharged intake systems. It fits snugly between boost hoses and hard pipe joints, ensuring consistent pressure and performance. Compatible with the following engines: VW T5: 1.9 TDI – AXB, AXC, BRR, BRS, BPC 2.