Amazon.com: Vacuum Pressure Switch, 1/8 in : Industrial & Scientific
Vacuum & Pressure Switches - A Complete Guide
Vacuum Pressure Switches | Gems Sensors
INDFOS Vacuum Switch RT121 PB, Range (-)1-0 Bar and Adjustable Differential : 0.09 to 0.4 Bar (One SPDT microswitch) : Amazon.in: Industrial & Scientific