Sangamo Time Switch is solar dial quartz controlled with battery reserve and day omission, 3 pin base. The ON operation always tracks SUNSET while the OFF operation can be made either to track SUNRISE or to occur at a fixed time between 8:30pm and 1:00am. The Q550 comes in 4 separate ‘Zones’ relating to your latitude, see reverse for map. A “day omission” device allows you to select any number of days in the week on which the switching cycle can be disabled.