DURABLE & STURDYOur flat washers are solid stainless steel. No exterior finish, no coatings, nothing but the finest 100% 18-8 (304) stainless steel. You'll never have to worry about the "stainless steel coating" chipping because there is none! | COLORFULCountersunk Washer made of Aluminum alloy, light weight, high strength, corrosion resistance,CNC machined for precision.Increased strength and precision. Compatible with:RC Models Cars, DIY Drone ,Aircraft , FPV frame,etc. | PREVENT LOOSENINGsourcing map washers are made with Marine Grade 304 stainless steel.Spring washers can prevent nut from automatic loosening, mainly used for occasions with vibration load or alternating load, tighten to prevent loosening. |