I was unhappy with the corner plates available for the Black Widow so I designed my own. These are 70H X 90W and 4.5T with 4mm holes and includes left and right sides. They are sized to have clearance under the bed and the raised ridges are left slightly sloppy so you can fine tune squareness. Includes 2 pairs so print it twice for all four corners. Also includes separate left and right singles.