Michael R. Freeman , Dec 03, 2006; 04:41 p.m.
Only Nikon brand 39mm filters will fit these holders. Standard 39mm filters will not fit (different thread pitch, threads on outside of rim). Any Nikon brand filter listed as 39mm *is* the filter for these holders.
You don't actually need a filter installed in the holder, as long as the holder itself is installed to keep dust out of the lens. I believe all of the 39mm filters have been discontinued (no current lens uses this size), but Cameta Camera has occasionally auctioned Nikon 39mm filters on eBay. Not sure if they have listed the L37c (UV), but worth a check. Other sellers occasionally list this particular filter.