I've got a 170 Lightforce lamp, and have made a ring to protect the filter from being scratched, when placed down. Made from 1.2 aluminium sheet 30mm wide, and being a sug fit to the filter,stays in place. The ring is welded together, and weighs nothing! Trimmed up with black duct tape, also stops any back glare! Made a few for mates, and they all approve!