I'm not going to link because I only have hard catalogs right now, but they do have websites, so you all can dig the out....alternate companies:
University Products, Gaylord Brothers, The Metal Edge, Archival methods (as mentioned above), TALAS, Archivart, Conservation Resources Int'l, and Hollinger.
Hollinger has been around forever--they're a long time supplier for archives goung back 50+years. their catalogs never seem to change (nor do the prices). they have an offshoot now, called geneology supply or something like that to cater to the non-institutional customers...
Gaylord is another good one--they have a number of different catalogs, but the main catalog is about 650 pages long, covers everything from archive supply, conservation, photo storage & handling, to library materials and furnishings. University Products is also similar to Gaylord in this respect. Brodart is another one, but more library supply.
The Metal Edge and Archival Methods are more recent entires. CRI has been around longer, and they carry a lot of technical conservation products on top of the microchamber enclosures and polyester sleeving as well. They have a presence in the UK as well as the US. Archivart, TALAS etc--more bookbinding, library supply, mounting materials etc.
They're all about the same, it just depends on what sort of products you're looking for. The place I work for has done business with just about all of them, but for whatever reason, LI is no longer on our vendor list. I don't know if it had to do with the purchasing system or what, but they dropped out late last year. About 5 years or so ago, they quyit carrying some of the storage products we use anyways, but I always liked their apollo & renaissance papers.... oh well, there are other companies out there.
btw--on Archival Methods site, Dennis Inch is mentioned...he's from LI at an earler time, and co-wrote the book, "The Life of a Photograph", which covered a lot of ground, including a big chunk of it on conservation matting....