On 16 December, the Finnish government signed a contract to purchase 44 aircraft: a F2A-1 variant designated Model B-239E by Brewster. Unlike other fighters already in service, the F2A-1 and B-239E lacked self-sealing fuel tanks and cockpit armor. However, the B-239E was built with a more powerful engine than the F2A-1, in the form of the Wright R-1820-G5, producing 950 hp (708 kW), and the capacity to carry four machine guns (rather than the two carried by the F2A-1). The B-239E was also "de-navalized" before shipment: equipment such as tailhooks and life raft containers were removed. The upgraded engine and slightly reduced net weight (i.e. from the omitted armor and de-navalization) resulted in an improved power-to-weight ratio and better general performance.