Model 103FF Outside Screw and Yoke (OS&Y) gate valve with resilient wedge, The stem is pre-grooved for installation of a supervisory switch. The interior & exterior have an electrostatically applied fusion - bonded epoxy coating of 0.2 - 0.5 mm as per AWWA C-550. Rapidrop 103FF OS&Y gate valve is used in a fire protection sprinkler system, the stem and stem nut are located outside of the body of the valve which makes it easy to see if the valve is open or closed. If the full length of the stem is visible then the valve is open, if the stem is not visible then the valve is closed. Rapidrop OSY2 supervisory switch is available to monitor the open or closed status of the 103FF OS&Y gate valve.