Abstract: A trigger device enabling a larger actuating force to be restrained by a smaller control force comprises a housing in which is rotatably mounted a primary lever biased to rotate from a cocked position to a firing position by a tension spring. The tension spring is located such that the rotational bias to the primary lever is significantly greater in the firing position than in the cocked position. The trigger device is typically used for both automatic and manual release of compressed gas from a bottle to an inflatable life-saving aid by way of a piercing pin moved by a cam surface on a secondary lever which can be manually rotated by a toggle or automatically by the primary lever on the dissolving of a water-soluble tablet restraining the primary lever in the cocked position.

Abstract: A life-saving aid comprising an elongate inflatable tube provided with an automatic inflation device arranged to release CO.sub.2 gas to inflate the tube when immersed in water or manually triggered. When inflated, the tube forms an elongate substantially linear cylinder sufficiently rigid to at least support its own weight when held horizontally from a proximal end. The tube is compact when deflated, is throwable, has significant tensile strength, and is designed so that after inflation and use, gas may be readily excluded via oral inflation tube by releasing the valve and rolling the tube from distal end toward proximal end.