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</head><body><p style="font-size: 12pt; font-family: helvetica, arial, sans-serif; color: #333333;">Hi Rita - The 2 adapters I have are the type with a locking nut rather than set screws. They just slide over the B mount and lock into place with a slight turn of the locking nut. They just don't seem to work on the Illumina lens though, neither of them. They work wonderfully on some Zeiss Distagons I have, so I'm having a hard time wrapping my head around that. I think the adapters were made by Optex.</p><div class="io-ox-signature"></div><p style="font-size: 12pt; font-family: helvetica,arial,sans-serif; color: #333333;" class="default-style"></p></body></html>