ことりコ 5 If you have any old slr or rangefinder lenses that need opening then this tool is pretty useful. It makes opening them much easier and reduces the risk of causing any danage to the glass or body ofthe lens.The tool is quite heavy and the fine points of the wrench fit easily in the hole of the lens.The tightening mechanism of the wrench, when adjusting for the diameter of the lens, is simple but works well. It can sometimes feel a little unstable so be sure to have a solid workspace underneath.The point ends and also the flat head screwdriver style end were both useful for opening up the lens mounts to get the glass out for cleaning.This tool has a decent cost-performance ratio and is definitly useful if you have any older style lenses that require opening for home cleaning or repair.