Multiple manufacturers provide door and window contacts, we use the George Risk Industries or GRI brand more than any other. There are too many different types of contacts available to list them all here and there are contacts designed for just about any application that you can imagine. Contacts range in size from 1/4" diameter to large garage door floor mounted contacts. We typically stock contacts for any typical door or window application that exists but if we run up on something unique, there's almost always something available that's made specifically for that use. You can view GRI's web site here.
SEM Security Systems
a division of Southeast Mobility Inc
Door & Window Contacts