They sell under 2500 Euro VAT (Value Added Tax) forms and over 2500 Euro VAT forms and deal with UTAP sign ups.
VAT forms can be used at almost any vendor off base in Germany. The person making the purchase is tax exempt when they present a VAT form to a vendor. The German sales tax is 19%.
(Utility tax avoidance program)
They require a copy of orders, rental agreement, and the first bill from the electric company (RWE)
The only utilities available through the UTAP are electric and gas.
Source: Spandahlem FSS