MKT Fastening zinc plated taper bolt anchor with expansion nut. Required hole diameter equals anchor diameter. Variation in hole size can be accommodated by turning the expander nut. Equipment may be removed and replaced. The bolt is simply re-inserted and torqued to obtain original holding power (the nut stays in the hole). Bolt can be removed and re-used with a new nut after cleaning and lubricating the threads. Grade 5 zinc plated. Strength - the highest shear strength of any expansion anchor. Withstands vibratory loads. It works in a bottomless hole. Made in USA. Do not use in brick or block. Tested by Pittsburgh Testing Laboratory PG-2170.