Commercial Electric Thermostat 0-100F, 84"Capillary, 3/8" x 4-1/2" Nickel Bulb. The 5000 Series (Model D1/D18) thermostat is DPST, for A.C. operation. Direct acting (contacts open on temperature rise). All 5000 Series have a positive off feature. U.L. file number E12103.