- Thru Hull Plumbing Fitting - Made of Marine Grade 316 Stainless Steel, very tough and resistant to corrosion - Fit for 22mm or 24mm inner diameter hose pipe - Fit for Webasto, Planar, Eberspacher, Chinese Diesel Parking heaters var4 - Surface polishing,corrosion resistance and durability in the saltwater environment,Easy installation With screws