In our standard 4um material, currently the largest available ID is 30mm.
All Cogent prep columns including the 30mm are supplied with threaded hardware. Larger IDs such as 50mm generally must be flanged or bolted which we do not supply. You may want to consider the 21.2mm ID as well, since cost increases with larger diameters.
Our Cogent prep columns are made to order so delivery could take up to 20 business days but it is always best to check with our customer service department for current information.