Product details:

Non-slip treads are a permanent and easy way to make stairs, decks, ramps, walkways, and more safer from the danger of slipping. These aluminum safety treads are rust-free and can be used indoors or outdoors, for commercial or home applications. The stair treads can be installed quickly and easily into nearly any type of surface - just drill into place with the appropriate hardware. (#8 stainless steel screws are recommended for wood; Tapcon anchors are recommended for concrete installation.)