ISO D Die Spring, Heavy Duty, Color Red, Chrome Silicone Alloy Steel, Finish Powder Coat, Overall Length 3-1/2 In., Outside Dia. 1/2 In., End Type Closed & Ground, For Hole Size 1/2 In., For Rod Size 9/32 In., Spring Rate 63.4 lb./in., Meets/Exceeds ISO10243