San (letter) San (letter) San (Ϻ) was an archaic letter of the Greek alphabet. Its shape was similar to modern M, or ϡ, or to a modern Greek Sigma (Σ) turned sideways, and it was used as an alternative to Sigma to denote the sound . Unlike Sigma, whose position in the alphabet is between Rho and Tau, San appeared between Pi and Qoppa in alphabetic order. In addition to denoting this separate archaic character, the name "San" was also used as an alternative name to denote the standard letter Sigma. The existence of the two competing letters Sigma and San is
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.