Based on visual evidence from the provided images and market research for vacuum process control components, here is a professionally optimized eBay listing for the MKS Instruments Type 649B Pressure Controller.
The MKS 649B00422T23C3VR is an integrated pressure controller that combines a capacitance manometer, a proportional control valve, and closed-loop electronics into a single compact package. It is specifically designed to maintain a precise pressure in a vacuum chamber by regulating the flow of gas, such as Argon (Ar), at rates up to 2000 SCCM.