Coworker gave me couple of these 500 LED panels with barn doors. Unfortunately he didn't have mounts for them so I needed to figure something out. As these panels are pretty old and of unknown manufacturer I had to design my own mounting system for light stands. Mount consists of two 3D printed inserts and a bridge between the for stronger connection. Both inserts and bridge have holes where standard tripod 1/4" thread brass insert was melted in with soldering iron. You assemble it by installing inserts into the opening slide and moving them into position one by one. Then bridge is screwed to it using 1/4" 3/4 inch long bolts. Bolts not only hold bridge but also protrude on the other side preventing mount from sliding freely. Then bridge is attached to the light or tripod mount that has standard 1/4" thread. I've mounted lights on mini ball-heads that's capable of holding the weight (barely).