The standard safety sensor receiver and transmitter must have clear line of sight for the focused IR beam. In the event this path is broken while the garage is in the closing operation, the operator is signaled to stop and reverse the door operation up. Proper operation of these sensors require the transmitter and receiver to be aligned. Common causes of garge doors which don't close when triggered through a wall clicker or remote is due to these sensors being mis-aligned. These small sensors are susceptible to falling out of alignment when accidentally bumped by a broom, a rolling ball or a sneaker. Infinity Shield uses patented Technology to require no alignment and is not susceptible to failures when in contact with accidental bumps.