Durable Material: Made of heavy-duty steel tube with water and rust-proof finish. It is sturdy, rust-proof, wear-resistant, durable, and can be used for a long time..Save Energy and Time:With a 500-pound load-bearing capacity, Roof ladder hooks with wheels has a strong load-bearing capacity. At the same time, the universal wheel design enables the stairs to be easily connected to the roof, saving energy and time..Adjustable Hook Length: Four mounting holes are designed, you can choose the appropriate mounting holes according to the different spacing of the ladder to achieve the desired effect. Extension ladder accessories can also be attached to extended ladders..Ladder Hook Wheel: The universal wheel makes it easier to slip the stair onto the roof, saving labor and time, can be attached to any style extension ladder. Includes: 2 ladder roof hooks with wheel. Both hooks fit over the top 2 rungs of the ladder & hook over The roof edge..Compatibility: This roof ladder hooks are the ideal method for securing the ladder to the rooftop. Adaptable. Easily attach and detach the roof hook for more streamlined work. Smooth. Included is a ladder hook wheel for much more smooth movement. Fits any style of extension ladder, fiberglass or aluminum.