What Is a Special Item Number (SIN) on the GSA Schedule?
A Special Item Number (SIN) is a category of products or services on the GSA Schedule. You're awarded the SINs you offer, and you can only sell what's under them.
Special Item Number (SIN) in plain English
The Schedule is divided into large categories, then SINs within them, such as one for facilities maintenance or one for IT professional services. Each SIN is tied to a NAICS code, whose size standard decides whether you count as small for orders under it.
Agencies pick SINs when they send a request for quotes in GSA eBuy, so the SINs you hold decide which requests you see.
Related terms
- GSA Schedule: The GSA Schedule (Multiple Award Schedule, or MAS) is a long-term governmentwide contract agencies use to buy commercial products and services.
- GSA eBuy: GSA eBuy is the site where agencies send requests for quotes to GSA Schedule holders. Only Schedule holders can see and answer them, so they aren't on SAM.gov.
- eOffer: eOffer is GSA's online system for submitting an offer for a Schedule contract and, after award, changes to it (eMod).
- Small business size standard: A size standard is SBA's cutoff for counting as a small business in an industry. SBA sets one per NAICS code, in average annual receipts or employees.
Put it to work
Looking for another term? Browse the full glossary or the government contracting glossary guide.
Cyrus Hakimi writes and edits these definitions, using AI tools to help research and draft them, from the FAR, SBA rules and SAM.gov documentation. They're general information, not legal advice. Rules and thresholds change, so confirm the numbers on the official source before you act.