The Lovejoy RunRight belt and chain tensioners offer longer belt and chain service life by transmitting constant torque. It is ideal for roller chains to be periodically tensioned so that it could transmit torques efficiently. Since roller chains are positive power transmission components in machinery or assembly lines, their function is proportional to quality. Due to use, these chains elongate from 1 to 3% of original length. Easy to install and maintenance-free, these tensioners also are designed for increased efficiency, reducing overall energy cost. The tensioners come in a wide variety of accessories and are available in seven standard sizes.