What is the difference between W1 and W2 material?

W1 is the classification we use for galvanized steel hose clamps (according to DIN3017) that are used in no-corrosion environments. W2 is the classification for stainless steel hose clamps (combination of AISI430 and zinc plated screw) that can be used in corrosion sensitive environments. The W4 (all parts AISI304) hose clamps are also stainless steel hose clamps that are fit for environments even more corrosion sensitive than W2 hose clamps can handle. And last but not least, W5 (all parts AISI316) for very aggressive corrosive environments.