This guide wheel not only eases the angular traition to the extruder but offe very little resistance in doing so. Should be used in conjunction with an upper filament guide. It is large enough in diameter to not present a tight turning radius radius from the upper filament guide. This model requires that you captivate the 608 bearing by gluing the wheel halves together. The wheel spacer is glued to the strut. Because of material differences and conditio the axel pin may require some sanding and the spacer and hub holes may require drilling out to 8mm to achieve an interference fit. The strut uses 5mm hardware to securely attach to the extruder bracket. It is best to remove the extruder to facilitate the itall and you will probably have to grind or sand the heads of the screws for better clearance. All parts are laid on the flat side for printing and the only supports needed are just a few under the tab that slips over the stepper bracket edge. It takes just a little finesse to snap it in.