GSA Federal Acquisition Service
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Wildland Fire & Equipment
Industrial Services & Supplies

Look here for portable generators, batteries, chargers, portable light towers, restrooms & restroom shower buildings, bathtubs, water closets, showers, faucets, and constructions supplies.
Source
Description
MAS Multiple Award Schedule - Available offerings include commercial goods and services organized by 12 Large Categories, corresponding Subcategories, and SINs.
56 BUILDINGS AND BUILDING MATERIALS/INDUSTRIAL SERVICES AND SUPPLIES - This Schedule provides a full range of commercial products and services covering such areas as buildings and building materials/industrial services and supplies. In addition, this program offers energy saving building supplies, alternative energy solutions, and related services.