ISO D Die Spring, Extra Heavy Duty, Color Yellow, Chrome Silicone Alloy Steel, Finish Powder Coat, Overall Length 5-1/2 In., Outside Dia. 3/4 In., End Type Closed & Ground, For Hole Size 3/4 In., For Rod Size 3/8 In., Spring Rate 276.9 lb./in., Meets/Exceeds ISO10243