(225in1 set) -225 O-rings with separate transparent plastic storage box. (VMQ) - Standard silicone, temperature range from -22 ℃ ℉ (-30 ℃) to 392 ℉ (200 ℃). (Hardness) -50 hardness tester (Shore hardness), used for permeability resistance. (Multiple sizes) -15 different metric sizes, with outer diameters ranging from 6mm to 20mm. (Application) - Widely used in hydraulic and pneumatic seals, pressure valves, gas compressors, reaction valves, heat exchangers, boilers, filters, mechanical seals.