REVISED DESCRIPTION: Used Durst "NEDOPLA" #17175 52mm OD (2") enlarger lens board with 25mm threaded hole for older enlarging lenses. Our research suggests this fits the M300 and M301 enlargers but do check the dimensions in your enlarger before buying. 

WHO WE ARE: Oddog2 is a husband/wife team, home-based small business specializing in the buying/refurbishment/selling of primarily photographic equipment. We do occasionally have other types of things to sell that come to us as a result of our search for camera-related items. We have 47 years of experience (22 years as a hobby, 25 as a full time effort) with photographic equipment, both as a shooter (17 years newspaper photojournalist) and as a collector/restorer/seller. We have been on eBay as Oddog or Oddog2 since September 1999.