Glass fabric laminated with a flame retardant epoxy resin. G-10/FR4 is strong, machinable, moisture resistant, electrically insulating, and flame resistant. This Product is Manufactured in China. Diameter: 2"; Diameter Tolerance: (-0.031" - +0.028"); Length: 1 ft.; Length Tolerance: Oversized. Color: Yellow; Tensile Strength: 38,000 psi; Tensile Strength Rating: Excellent; Impact Strength: 14.0 ft. - lbs./in.; Impact Strength Rating: Excellent. Coefficient of Friction: Not Rated; Friction Rating: Not Rated; Water Absorption: 0.0015; Water Absorption Rating: Good; Hardness: Rockwell M110. Density: 0.072 lbs / cu. in.; Temperature Range: 280° F; Specifications Met: UL 94 V0.