Hook End—Hook into closed holes, such as hanger bolt eyes. These springs work best when kept under tension, as they're more likely to slip off than loop-end springs when tension is released. Also known as machine hook ends.

Spring Steel—Strong and resilient, but best suited for dry environments since moisture will cause these springs to rust.

Corrosion-Resistant 302 Stainless Steel—Won’t corrode from exposure to moisture and mild chemicals, including ammonia often found in cleaning solutions. These springs are easier to extend than steel, but can’t handle as high a load.

Minimum Load—The amount of force required to start extending the spring.

Maximum Load—The amount of force required to fully extend the spring.