The biggest defence works in the Westwall were the so-called 'B-Werke'. 32 of them were built mainly along the German-French border. Work on the B-werke started in 1937 and the last ones were finished in 1939. They were built in Baustärke B-Alt (1,5 m thick roof and outer walls), which was the strongest Baustärke in 1937. The standard weaponry consisted of 2 Sechsschartentürme with each 2 MG-34s, one 5 cm automatic mortar M19 in an armoured cupola and one automatic flamethrower. All the gunrooms, the crew, sentry and communicationroom can be found on the first floor. The lower floor housed the restingrooms, machinery, washroom, toilets, kitchen, storage for water, oil etc. and the medical room. The machinery and electrical equipment were the most modern of their time. Around 100 soldiers were stationed in every B-werk. Henk Adriaanse payed a visit in 2016.
The bunker in Besseringen is the only intact B-Werk left.