The contract between Rheinmetall-Borsig and the Artillerie Inrichtingen (dated 24th January 1936) called for delivery of four 37 mm pieces:
- 2x 3.7 cm Inf. Kan. L/50 on split carriage with balloon tires;
- 2x the same on wooden wheels.
[Nationaal Archief 2.13.86 - Inv.No.2525]
According to Mr. Allert Goossens' study on air defences at the Grebbeberg (
http://www.grebbeberg.nl/bibliotheek/data/luchtmacht_en_luchtafweer_v28112004.pdf, page 11, note 5) twenty 37 mm Rheinmetall AA guns were ordered, of which only three had been delivered. These guns were stationed at Scheveningen for trials (the latter can also be found in Molenaar's work on Dutch air defence in May 1940).