RS Pro worm drive hose clips are manufactured in 304 grade stainless steel. They are tested and BSI Kitemark certified according to British Standard 5315:1991. OBBSW4 is made entirely from AISI-304 stainless steel, austenitic grade 18/8 Stainless Steel (18% Chromium with 8% Nickel), which is comparable to W4 DIN3017 (German Standard). The hose clip is optimized for hose protection by raising the band edges and precisely stamping the band to provide a smooth underside surface. It provides the ultimate exterior hose wall protection with a non-perforated band, which gives more protection to the soft hose surface, during the installation and usage.