Usually, as like the locks parts, we suggest use stainless steel(AISI304/AISI316) to produce it, because it have nice rust resistance and good performance.

The material of item code (EM50 CAME ZARELHO) can use 17-4PH or Fe2Ni(MIM4605) ,17-4pH is a kind of stainless iron and its rust resistance is better than iron, and have some hardness. MIM4605 is a kind of iron, if you use MIM4605, we suggest that do surface treatment to protect its surface.The below is material info, for your reference. Please tell us which material you want so that we can arrange to quote for you.

BTW, the price of other items are already finished. Regarding different price of 5000pcs/50000pcs, it is same because i want to give your best price.