Got in a Tronxy X5S to X5SA upgrade kit from www.customize3d.biz and it came with a mosfet for the heated bed and while it came with a holder for it I wanted to something a little different. This is designed to bolt to the frame by 2 m4 bolts and T nut I allowed for the screw driver to pass through the side of the box to tight the mounting bolts. I will have a matching enclosure foe the control board once it has been test printed ... I have not printed this item yet But I'm sure it will work. the lid should be able to be help on by 2 m3 bolts one from each side.