Most SEMS Screws are created as Machine Screws.
It is common for SEMS Screws to come with one or two pieces of washer, depending on the size and requirement.
Sometimes Spring Lock, Flat, External Tooth or Internal Tooth Washers are used in the assembly. SEMS Screws are made with carbon steel or stainless steel.
Mostly SEMS Screws are coated with zinc or yellow zinc to help resist corrosion.