Trade Fair to Heverle in 1920

This cover was sent from the Trade Fair (Foire Commeriale) in Brussels to Heverle on 13 April 1920.

Characteristics: 5c+5c single and 10c King Albert in trench helmet Franking of 15c (exact amount) Circular 1 cancel (mailman's cancel) Some discoloration
Estimated value: $40