ISO D Die Spring, Heavy Duty, Color Red, Chrome Silicone Alloy Steel, Finish Powder Coat, Overall Length 3 In., Outside Dia. 2-1/2 In., End Type Closed & Ground, For Hole Size 2-1/2 In., For Rod Size 1-1/2 In., Spring Rate 3528.8 lb./in., Meets/Exceeds ISO10243