Weco Butterfly Valve Weco Butterfly Valve provides the reliability and efficiency in the flow control. Available sizes 2 " - 24" . Pressure: 175 psi. Type: Wafer, Notched, and Lug. Model 12. Size 2 " - 12" . Wafer Type, short neck. Model 12N. Size 2 " - 6" . Notched type body, short neck. Model 22. Size 2 " - 12" Wafer Type, Long Neck. Model 22L. Size 2 " - 24" . Type Lug, Long Neck.