Ameristep Step-Up Tree Step - Two-inch long threads on these self-tapping screws make installation and removal easy. The sturdy 4-inch step area makes climbing and descending less precarious, and you can set them at points that are comfortable for your height. Best of all, no more lugging around a ladder or step frame in the woods, since you can easily fit several of these in your pack. Self tapping threaded point for easy installation Thread length is 2" Step area 4"