Under the MAS Program, GSA issues long-term governmentwide contracts that provide federal, state, and local government buyers access to commercial products, services and solutions at pre negotiated pricing. The GSA Schedule is structured to support the 12 large categories established by OMB under the category management approach of smarter buying. The Schedule is further divided into subcategories and Special Item Numbers, or SINs, that are aligned to NAICS codes to simplify the process for buyers and sellers to understand the scope of GSA’s offerings and find what the products and services they are looking to buy or offer.