About 1951 the Bialaddin 300x was superseded by the Bialaddin 305. This is a complicated model there being several versions of this lantern. We seem to have two different styles at the same time. One used by the Military with a 1 1/4" filler cap and one for the civilian market with a 1" cap. This is the first time the 1" cap is seen. A new style hood also makes it's first appearance, stamped from a single sheet of steel. Obviously a cheaper proposition to the previous two piece hood it would seem to have been made initially for the military lamps. Apart from the hood the military 305 is exactly the same as the 300x it replaced, as is the civilian version apart from the 1" cap. The new style hood and the two piece continued to be mixed and matched with different models up to about 1979 when the two piece hood disappeared from the scene. Why W&B made two styles of hood at the same time I do not know. Maybe they thought the two piece more attractive, better at dispersing upward heat. I would only be guessing! Military contracts must have been very important to Aladdin and W&B because in 1954 when the Bialaddin 310 was introduced the Army obtained their own variation of a new style Bialaddin 305. It had the new alloy frame used on the 310 but had a wide collar to support a straight sided glass as the previous 305 variant. I have seen these lanterns dated between 1954 and 1964 but they probably carried on till 1968 when the same model became the Vapalux M1. See posts for 1951-54 Bialaddin 305 Civilian Version and 1954-68 Bialaddin 305 Army Version.