Our Stick Grip has a 1″ diameter hole in the bottom to allow your stick tube to fit 2.125″ up inside it *.gif . A 29/64″ hole is drilled 0.5″ down from the top of your stick tube ( at the proper clock code to ergonomically fit your hand and wrist ) for the Stick Grips lower boss and screw to clamp through, and the Stick Grip halves to clamp over. You DO NOT *ever* glue our Stick Grip to your stick tube!!! NOTE: at Oshkosh 2003, we were told of an RV-8 builder who was killed when his glued on rubber grip he was using as a stick grip in his plane came loose and UP, jamming into the underside of the instrument panel!!! Spacers are available if your aircraft stick tube OD is less than, or greater than, a standard 1″ OD stick tube [ i.e. — to fit Lancair 200’s, 235’s, 320’s, 360’s and older Legacy’s ( newer Legacy’s are now 1″ stick tubes ), use a short 3/4″ spacer ; for Canard’s, Lancair IV’s, Lancair ES, Nemesis NXT, and any side stick aircraft, use a long 3/4″ spacer ; or to fit the Van’s RV-4, 6, 7, 8, & 9, and Harmon Rocket, co-pilots’ — and the Van’s RV-10’s, RV-12’s, RV-14’s, Glasair’s, Glastar’s, F-1 Rocket’s and Expresses pilot AND co-pilot — use a 7/8″ spacer to adapt your aircraft’s stick tube ). For the larger 1.125″, 1.25″, 1.375″ or any size OD stick tubes — such as used in military aircraft, Mig’s, T-38’s, L-39’s, T-34’s, P-51’s, SN-J’s/T-6’s, Yak’s, CJ-6A’s, Marquette’s, Extreme 300’s, and Falco’s, for example — a custom 5″ long spacer will fit inside your larger ( custom spacer mounting instructions ) than 1″ OD stick tubes ID nicely ( see ‘Pricing’ tab above, and provide your stick tube ID on our order form, if you want us to make it for you ). A simple Stick Grip Installation Drawing is provided with your Stick Grip order ( see “How to Install” *.pdf above ). The Stick Grip splits in half for *very* easy maintenance. Replacement parts can be easily installed by you, and are available by simply contacting INFINITY Aerospace via the Excel order form. NO other Stick Grip in the world has this much versatility at this low of a price !