Very simple 2-piece y-axis tensioner that uses a wing nut and #8 machine screw to adjust the belt tension.  The tensioner housing fits in the slot of the front 2020 rail and uses the screws and t-nuts from the original bearing housing to lock it into place.Note: You can easily put too much tension on the belt with this so if it makes a lot of noise, loosen it a little at a time until it's quiet.