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
Safety unharmful function of an object or organization. It is used in order to ensure that the object or organization will do only what it is meant to do. It is important to realize that safety is relative. Eliminating all risk, if even possible, would be extremely difficult and very expensive. A safe situation is one where risks of injury or property damage are low and manageable. There is a distinction between products that meet standards, that are safe, and that merely feel safe. The highway safety community uses these terms: Normative safety is achieved when a product or design meets