Their catalog is a 12 page list of items with a few pictures. Their prices on MREs and Israeli gas masks are legendary. Excellent sources for parts and accessories for the popular weapons, lots of military manuals, and lots of small needed items at good prices. They have the best prices I've found on Cylalume sticks, signal mirrors, compasses and other like items.
Service is prompt.
They run adds in American Survival Guide frequently. They do not have a huge variety, or a fancy catalog. They concentrate on specific areas and do a good job in those areas. SI is probably the largest survival mail order supplier around. They have the widest selection of products of any single supplier.