Nine-volt battery batteries were formerly made in this size. They had higher capacity than the then-standard carbon-zinc types, a nominal voltage of 8.4 volts, and very stable voltage. Once used in photographic and measuring instruments or long-life applications, they are no longer manufactured as mercury is highly toxic and accumulates in the ecosystem, posing a risk to humans and wildlife. Most battery voltage testers and chargers that can also test nine-volt need another snap clip to hold the battery, while cylindrical batteries often share a holder that may be adjustable in size. Because of the proximity of the positive and negative terminals
International Institute of Risk & Safety Management International Institute of Risk & Safety Management The International Institute of Risk & Safety Management (IIRSM) is a professional membership body for safety practitioners worldwide. It is a registered British Charity (number 1107666) and UK Company limited by guarantee (number 5310696). IIRSM have two main membership streams. A “health and safety practitioner stream”, for those qualified or studying to be health and safety practitioners, and a “specialist stream”, for those who are qualified to degree or NVQ level 4 (or equivalent) and above, in a profession associated with health and safety practice but who hold no health and safety practitioner