Thrd/SW Valves toolbar: Thrd/SW Check 
Command line: CHKS/CHKT
Places a threaded or socket weld check valve in the X-Y plane.
last point
Starts the plain end of the valve at the last point of the previously-created component.
Start
Places the start point of the component at the default start point.
Middle
Places the valve at its center.
otherEnd
Places the start point of the component at the other end.