The check valve uses a linear motion to move the check member out of the bearing surface. They have a housing that features a spherical cavity around the port area to regulate process flow when used with a drive assembly. Many single-seated valve bodies use a cage or retainer design to hold the seat, provide direction to the valve plug, and provide a means to determine the specific flow characteristics of the valve. Cage or lock-type single-seated valve bodies can also be easily modified by changing trim parts to alter flow characteristics or to provide reduced flow, noise reduction, or cavitation reduction or elimination.