Oil-fired space heater, or similar article
Oilstove
Oilstove
Oilstove
Oilstove
Oilstove
Oilstove
One piece wide stoker key for stokers feeding steam generator fu
Operating room ductwork
Operating room ductwork and headwall
Orifice plate for a radiator valve
Oscillator sprinkler
Oscillator sprinkler
Outdoor air intake valve
Outdoor fireplace
Outdoor fireplace
Outdoor stove
Outdoor-heater offset arm
Outlet fitting for a pipe
Over-pressure valve for ventilation