The TBS Gemini Body Retention System was designed to: Two loops and two hooks are printed, and attached to the top edge of the bottom lexan cover with Goop (available at home improvement stores). An o-ring is attached to each loop, stretched across the top cover, then attached to the hoop on the opposite side of the cover. I printed these parts on my Solidoodle 4, with 0.3mm resolution, and 1.0 infill. In addition to the printed parts, some Goop adhesive and some 2.75-3.25" elastics or o-rings are required. In addition to the loop/hook/o-rings, I recommend installing a strip of silicon fuel tubing (available at RC hobby stores), along the perimeter of the bottom lexan cover. The silicon will protect the PCB/ESC traces from impacts from the edge of the lexan cover, particularly during landings. See the instructions for more information! I hope you find these parts helpful. Enjoy! Print the parts; you will need 2 of each. Install the top and bottom lexan covers and choose where you would like the hooks & loops installed. If you are going to install silicon tubing, do this first. The silicon tubing needs to be slit lenth-wise, an then placed along the edge of the bottom cover. The hooks and loops should be placed just below the silicon tubing, not contacting it. Mine are placed approximately 2mm below the silicon tubing. Remove the bottom lexan cover. Scuff the area where the hooks and loops will mount. This will help the Goop (adhesive) achieve better adhesion to the lexan. Follow the Goop's direction to install the loops. I took my time and did them one at a time, following the directions, and holding each hook or loop in place for the first few minutes. After that, I removed the silicon tubing to get it out of the way. Do this for both hooks and both loops. Once the Goop has dried, slip one end of an elastic or o-ring through one of the loops, from the bottom, poking it through about an inch. This take the other end of the o-ring/elastic, and pass it through the loop, then draw it tight. This will keep the elastic/o-ring from getting lost. Do this for both loops. Go and fly! I hope you find this helpful.