I purchased a pair of these off Amazon a few days and was stunned to find the designers had got their measurements wrong and they wouldn’t fit a standard quick release helmet buckle. They were also extremely thin and flimsy and not worth modifying so back they went. Frustrated and not wishing to mess around any more I made my own instead. I had so 25mm/2mm aluminium billet in my garage so I pressed and glued two 120mm pieces to form a nice 4mm piece and then cut, dremelled and sanded until I had what I needed. It works brilliantly and cost nothing. Really shouldn’t have been so lazy and just made one from the start. Avoid this one!