
These are VT fuzes of the ring type, similar to the T50E1 series. They are designed to detonate the bomb at a point above the earth which will give effective fragmentation. The T91 and T92 differ from the T50E1 group in that they have greater sensitivity and are specially designed to be used for low level, medium level, and dive bombing. These ring type fuzes are especially sensitive to "passing" objects and therefore are useful in defoliating by blast and in getting roof top bursts in city areas.
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USNBD - Bombs and Fuzes, Pyrotechnics (1945)