The edges of the Feeler Gauges set is steel and polishing It ' s full of bright metal texture specially treated, smooth and doesn ' t hurt your hand Tapered Feeler Gauges set is steel, hardened and polishing for long time and accurate usage Feeler gauges for valves can fold into steel case with a thumbscrew, easy to carry, to take and safe to store The Feeler Gauges doesn ' t get rusty and easy to open The number of size are etching into the Feeler Gauges for easy identification, Manufacturer: HVRFJXI