The FM1D20 Series Electronic Time Controls are for ventilating, heating, cooling, lighting or other electrical loads in commercial and industrial applications. These one-channel time switches are programmable for 24-hour or 7-day schedules. They are intended for either panel, surface, flush, or DIN rail mounting. Flush and surface/DIN rail (A & E models) are completely enclosed in a plastic housing and include a terminal cover, dust cover and subbase for installation and hard wiring.