There are a couple bolt options. Mine is the simplistic version which requires a wrench. The bolt came from my "junk box" and was longer then necessary, hence the Nylon spacer on top of the bar. The Nylon spacer below the bar and bolt was drilled with a 1/16 inch bit to accommodate a cotter key. The prevents the bolt falling out when the "T" Bar isn't installed on the fuselage.