Rock Drills, Drill Steels & Bits The correct name for this tool is a jackhammer High efficiency rotary air hammer Drills various sizes of holes in stone or concrete Gauer Rental stocks several sizes Other Features include: We also stock steels in 7/8" x 3 1/4" and 1" x 4 1/4" We stock steels from 1 ft to 10 ft long in H thread (have limited assortment in D thread) Gauer also stocks an assortment of bits for sale