LoPro Two-Stage
Low-profile, Two-stage, Soft-start, Bellows-sealed Isolation Valves

photo - MKS LoPro 2-Stage Vacuum Valve

MKS LoPro Two-Stage valves achieve a soft pumpdown and vacuum system isolation in one common housing. A small bypass valve is integrated into the main isolation valve, simplifying setup and reducing costs. With the integrated soft pumpdown feature, turbulent flow is diminished preventing contamination buildup and damage. The bypass valve is user adjustable by selecting a micrometer or thumb screw adjustment option. Additionally, a fixed flow orifice can be sized for the application that is housed internal to the valve to prevent unwanted adjustment.

LoPro Valves are extremely reliable, with a lifetime that can extend to 1,000,000 cycles under clean conditions, greatly increasing system uptime. For an integrated two-stage solution please refer to our Integrated LoPro (ILP) products or or contact an Application Specialist by sending an email to MKS Instruments, or call 303-449-9861.

Features & Benefits:

  • Two independent valves integrated into one common housing
  • Optional adjustable conductance for variable pumpdown speed
  • Eliminates the need for small bypass lines
  • Reduced turbulence and contamination during pumpdown
  • 1,000,000 cycles MTBF (clean conditions)


MKS LoPro Two-Stage Valves are suited for high vacuum applications, specifically semiconductor or optical processing for which a cleaner environment is necessary. With the integrated slow pumpdown feature, turbulent flow is diminished, reducing particle contamination.


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Part NumberPriceQTY
LoPro™ 2-Stage ValveQuote Only

Need help?

Contact an Application Specialist by sending an email to MKS Instruments or call 303-449-9861.