Wingjoiner to attach wing panels with O-rings. It works very well to secure the RVJET wings and wing extensions using 3/4" x 15/16" size O-rings. For a more aerodynamic install it is recommended to cut out where these are placed. Either by freehand or with the user of a joiner: http://www.thingiverse.com/thing:127067 Installation: http://www.rcgroups.com/forums/showpost.php?p=24931069&postcount=497 This wingjoiner is designed to be printed using FDM 3d-printers (Solidoodle, Makerbot, Reprap etc). It has the same outer dimensions as the roiginal Dhook wingjoiner but a more robust construction The original Dhook-wingjoiner was originally designed for injection molding and wasn't really optimal for 3d-printing. . I've made some revisions but I have not yet decided which version that works best since my printer is currently off-line. Rev A - First revision since the Dhook and is designed primarily for FDM-printing. This has been test printed. Rev B - I opened up the design to more easily access the O-ring since it was a little too tight in rev A. This version is shown in the rendered pictures.