Romanization of Greek Greek numerals which employed the entire alphabet, including the nonstandard letters digamma, stigma, or sigma-tau (placed between epsilon and zeta), koppa (placed between pi and rho), and sampi (placed after omega). As revised in 2001, ELOT 743 provides for the uncommon characters to be given (in Greek) as $ for stigma, + for koppa, and / for sampi. These symbols are not given lower-case equivalents. When used as numbers, the letters are used in combination with the upper "keraia" numeral sign ⟨ʹ⟩ to denote numbers from 1 to 900 and in combination with the lower "keraia" ⟨͵⟩ to denote multiples
Electric torque wrench Electric torque wrench An electric torque wrench is a planetary torque multiplier or a "gearbox" mated to a brushless electric motor. At the end of the "gearbox" is a reaction device that is used to absorb the torque. This allows the operator of the tool to use the electric torque wrench with very little effort. These tools are primarily used anywhere accurate torque is required on a nut and bolt, or where a stubborn nut needs to be removed. These planetary torque multiplier gearboxes have multiplication ratios up to 4000:1. The correct torque output is adjusted by controlling the voltage.