The globe valve, shown in Fig., is constructed in such a way as to cause the flow of the fluid passing through it to change direction twice. The disc and the seat are parallel to the main flow path, and the disc is moved toward, or away from, the seat by means of a threaded stem. Due to its construction, the globe valve is ideal for throttling or regulating flow with a minimum of wire drawing and seat erosion. Another advantage of the globe valve compared to the gate valve is that it is cheaper to manufacture. On the other hand, the globe valve offers much more resistance to flow than does the gate valve. The unbalanced single disc type of globe valve shown in Fig. is seldom used in sizes larger than 305 mm (12 in.) due to difficulty in opening and closing against fluid pressure.