Extension Spring Ultra Precision 302 Stainless Steel Plain End Type Full Twist Loops Overall Length 4 1/2 In Outside Dia 0.500 In Wire Dia 0.063 In Load 16.34 Lbs Deflection @ Load 3.56 In Initial Tension 1.48 Lbs Spring Rate 4.17 Lbs/In Meets/Exceeds ASTM A313 and AMS 5688 Package 3