Maximizing Efficiency with SIN 339940 Office Supplies by TrueUniform Published: May 6, 2026 (2 days ago) Category Business Link Technical GSA Codes & Federal Branded Merchandise True Uniform is a trusted supplier of SIN 339940 compliant products, including GSA contract branded apparel and non-paper office supplies. We simplify federal acquisition by providing pre-negotiated, high-utility solutions for government agencies.