Extension Spring Ultra Precision High Carbon Steel Plain End Type Full Twist Loops Overall Length 1 1/2 In Outside Dia 0.500 In Wire Dia 0.063 In Load 18.80 Lbs Deflection @ Load 0.67 In Initial Tension 1.70 Lbs Spring Rate 25.5 Lbs/In Meets/Exceeds ASTM A228 and AMS 5112 Package 3