||Represented here is the later style of MA production from the Mazda company, which was operated by AEI Lamp & Lighting Co. at this time. The lamp has been considerably improved from earlier designs in the BTH days, most noticeable being the improved arc tube frame mount. The former frame often resulted in breakage of the arc tube and was particularly time consuming to manufacture. Use is made of stamped steel plates here which are sprung-loaded onto the arc tube ends and these offered a far better degree of cushioning against impact while also speeding production. Dating this lamp to the time of AEI's 1955 takeover of BTH is simple because of the fact that the packaging makes use of BTH material with AEI labels affixed over them.
It is interesting to note that this lamp also has an individual serial number etched into the arc tube, specifying the glass batch which was employed. The lettering C46 refers to the glass type (later known as A42 after the AEI and GEC glassworks merged), which had recently been introduced to replace the slightly softer C37 (A431) grade. C46 was a harder aluminosilicate glass made by BTH Chesterfield, and its introduction permitted a slight increase in luminous flux.
Seals at either end of the hand-blown glass arc tube are made to glazed molybdenum rods, each of which supports the main electrode on a moly T-piece. The main open-coled tungsten electrodes contain an emissive pellet of radioactive thorium oxide to facilitate starting and maintain efficient operation of the lamp. For heat retention purposes, a layer of platinum paint has been applied to the area of the arc tube immediately behind each electrode, and the threads of the cap have been lubricated with a graphite coating.