Extension Spring, Ultra Precision, High Carbon Steel, Plain, End Type Full Twist Loops, Overall Length 4 In, Outside Dia 0.500 In, Wire Dia 0.045 In, Load 7.50 Lbs, Deflection @ Load 7.39 In, Initial Tension 0.70 Lbs, Spring Rate 0.90 Lbs/In, Meets/Exceeds ASTM A228 and AMS 5112, Package 3