Our manual butterfly valves provide a low-cost alternative to bellows-sealed gate valves. A patented design allows the sealing disk to center itself when closing, with even pressure around the FKM O-ring seal. This design also helps to lower the amount of scuffing or rolling of the O-ring. Quarter-turn actuation, small footprint and the shortest possible gas path make manual butterfly valves the preferred choice for many applications. Manual butterfly valves have a vacuum range of 1x10-9 Torr. FKM seals are standard but other elastomers are available upon request.