All our borderless clip frames are produced on demand at our facility in Spencer MA using our Quadro clip system. Backing panels are 1/8 inch thick MDF (Medium Density Fiberboard) with grooves milled around the entire edge of the panel . Our exclusive clips snap securly into the grooves at any location. Any number of clips can be added and the clips can slide to any position along the edge of the frame for complete flexibility in assembly and hanging. Front panels are either 2mm. thick edge polished float glass or, for larger poster frames 0.040" thick optically clear PET plastic with an opaque protective peel away film applied to both sides. While assembling your poster frames make sure to peel off the opaque protective film from BOTH sides of the plastic panel. Clip frames are made to precisely match the specified image size of 4x6 inches. The clip frames will accomodate 3/16 inches of additional thickness so there is sufficient space for an image as well as a double standard thickness matteboard. Frameless clipframes assemble quickly and easily - no tools required. The clean borderless look works with virtually any decor or image. An excellent choice for framing images economically and with a professional look.