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
Risk and Safety Statements Risk and Safety Statements Risk and Safety Statements, also known as R/S statements, R/S numbers, R/S phrases, and R/S sentences, is a system of hazard codes and phrases for labeling dangerous chemicals and compounds. The R/S statement of a compound consists of a risk part (R) and a safety part (S), each followed by a combination of numbers. Each number corresponds to a phrase. The phrase corresponding to the letter/number combination has the same meaning in different languages—see 'languages' in the menu on the left. In 2015, the risk and safety statements were replaced by hazard statements and precautionary statements