I wonder how many others have had unpleasant experiences using these adaptors, caps etc. Mine are: 1) A clip in 39mm front lens cap which is deep enough to touch the glass of early collapsible Summicrons, and maybe others. I told them about this but they are continuing to sell what look like the same items. 2) A screw-to-M adaptor with wrongly machined face, making it useless. Have just emailed the Co. that sells these. Adrian.