This is an 1:8 scale model of a generic bicycle shock for a conceptual velomobile design model, which uses a pen spring (.219" OD x .188" ID x .500" L) to represent the actual shock spring, which was designed to actually function! The shock model is beveled on both parts where the spring attaches and the spring can be just pushed on to hold the pieces together — or for a more permanent attachment, the spring can be super glued to the shock parts. (The circular cage is used only to keep the two very small parts together after printing and with a little finesse, the parts can be removed without cutting it. Although very fragile and can be crushed easily, the cage might be used for some other purpose — like possibly an ear ring!?) Both the mount hole diameters for the shock model are .047" (representing .375" full scale) and because of the 3D printing process, will require some re-drilling by hand to clear overflow material. In addition, there might some loose material in the main body part that will require removal with a flat toothpick, in order for the parts to get full suspension travel. Hob-bits small brass screws will be used to mount the shock to the frame. The distance between the mounting holes is approx. .813" with .188" compression distance (representing 6.5" with 1.5" respectively full scale.) Thank you for visiting the NRB Spatialty shop!