English to German Bus/Financial Law: Taxation & Customs

Hi,

Does anyone know whether there is a proper German Term for "specific tax" in German, other than just translating it as "spezifische Steuer" or as "Produktsteuer"?

Context:
Specific tax is proportional in amount to the number of [product], regardless of price.

(please see also my question about ad valorem tax)

Thanks in advance!
Gabriele