 Small forts had two one-gun 12 cm turrets and a one-gun 21 cm turret.These were produced by Gruson, Creusot, Saint-Chamond, , and Chatillon-Commentry.Additional guns were supplied by Marcinelle-Couillet, but only at the Fort de Boncelles and the large forts at Namur, and by Vanderkerhove, unique to Liège's large forts.