The Simon Trickle Slot vents are the perfect solution for reducing condensation and moisture build up in and around the window by allowing the moisture to leave through the vent. Also, the frame vents provide a constant air flow through the window, helping to reduce the temperature on hot days without compromising on security. When there is no desire for the air to be flowing through the vent there is a close off latch on the internal vent fitting allowing the ventilation slots to be closed. Each purchase includes an internal vent fitting and an external vent fitting.