Bike Rack Back Box holder

A Plastic Box support for rear bike racks. The rack is a Decathlon model that costs 15€, with a distance of 116mm between parallel tubes in the rear, It's a press fit, a bit of sanding required to make it enter. The model can be secured with zip ties to the rack, although I didn't need to, the pressure is enough to hold it. 

A M6x40 screw fits inside the wheel in order to screw it through the base, which fits an M6 nut.