Choosing the right hose clamp: size and material Oftentimes we choose hose clamps from familiarity, by remembering exact size, shape, or material, when in fact we should consider the purpose of usage e.g. outdoor, indoor, engine bay. Different materials of hose clamps are appropriate for different usage. According to DIN 3017 Standard, hose clamps materials range W1-W5 as shown below: W1: Zinc plated iron - available in CR3, non-hexavalent chromate (Hexavalent chromate is prohibited in Europe). W2: zinc plated rscrew and stainless steel band&housing W3: 430 Stainless steel W4: 304 Stainless Steel W5: 316 Stainless Steel