Oval-head drill screws CR H DIN 7504M-stainless A2 5.5x25mm

Phillips (PH) screws, standardized in ISO 8764 (blades) and DIN 7962 (Phillips recess), are widely used. For screws with a Phillips cross slot, the flanks of the cross slots taper as the depth of the slot increases. With the PH system, threaded and self-tapping screws that are difficult to access can be tightened and loosened even from a slight acute angle to the screw axis.

Stainless steel refers to alloyed or unalloyed steels that contain at least 10.5% chromium and less than 1.2% carbon. Colloquially, stainless steel is also referred to as stainless steel (NiRo), although not all stainless steel is the same as "stainless".

Stainless steels are defined in DIN EN 10088-1 as iron alloys containing at least 10.5 per cent chromium and no more than 1.2 per cent carbon. The multi-part DIN EN ISO 3506 series of standards applies to mechanical fasteners made from stainless steels. Grade A2 is classified as non-acid-resistant. Austenitic stainless steels cannot be heat-treated and achieve their different strength classes through cold working to varying degrees.