SST Sensing’s optical liquid level switches are solid state, so there are no unreliable moving parts. They are compact, only protrude a small distance into the application and are able to detect small amounts of liquid.
The intelligent liquid level sensors have low sensitivity to ambient light and are not affected by foam when in air, or small bubbles when in liquid.
Their ability to survive in wide operating temperatures and harsh liquid media for long periods of time result in a very robust switch.
If our standard range of optical liquid level switches do not meet your requirements, housings, cabling and connectors can be customised to suit your application needs. We can also incorporate built-in features like PWM outputs and insensitivity to moving liquids.
See our range below.

Product | Mounting | Tip Material | Pressure Range | Temperature Range | Supply Voltage Range | Output Current | |
---|---|---|---|---|---|---|---|
![]() | Mounted from inside the vessel: M12x1, M10x1 Mounted from outside the vessel: M12x1, 1/2" -20 UNF, 1/4"NPT | Polysulfone or Trogamid | 7bar/ 101 psi max 20 bar/ 209 psi max | Standard: -25 to 80⁰C Extended: -40 to 125⁰C | 4.5 to 15.4 Vdc | Up to 100mA | |
![]() | M12x1 1/2" SAE 1/4"NPT | Polysulfone or Trogamid | 7bar/ 101 psi max | Standard: -25 to 80⁰C Extended: -40 to 125⁰C | 4.5 to 15.4 Vdc 8 to 30Vdc | Up to 1A | |
![]() | M12x1 1/4" NPT 1/2"NPT | Glass | 100bar/ 1450 psi max 600bar/8702 psi max | Extended: -40 to 125⁰C | 4.5 to 15.4Vdc 8 to 30Vdc | Up to 1A | |
![]() | Mounted from inside the vessel: M10x1 Mounted from outside the vessel: M12x1, 1/4"NPT | Polysulfone or Trogamid | 0 to 7bar/ 101psi max 0 to 20bar/ 209psi max | Standard: -25 to 80⁰C | 3.3 to 24Vdc (customer provides) | Up to 4mA (Customer provides) | |
![]() | 3/8"BSP 1/2"BSP 1/2"NPT 3/4" -16 UNJF | Polysulfone | 25bar/ 363psi max | Standard: -25 to 80⁰C Extended: -40 to 125⁰C | 4.5 to 15.4Vdc 10 to 45Vdc | Up to 100mA Up to 800mA | |
![]() | 1/2"BSPP 78mm long probe 1/2" BSPP 138mm long probe | Glass | 80bar/1160psi max | Standard: -25 to 100⁰C Extended: -40 to 140⁰C | 12 to 28Vdc | 25mA max. | |
![]() | M12, 4-pin, A-coded connector (see accessories) | Polysulfone / Trogamid / Grilamid | 32 bar (464 psi) maximum | -30 °C…+80 °C (-22 °F…+176 °F) | Liquid detected: >3 mA; Air detected: | NAMUR | |
![]() | M12x1 M10x1 1/2" -20 UNF 1/4"NPT | Polysulfone or Trogamid | 0 to 7bar/ 101psi max 0 to 20bar/ 209psi max | Standard: -25 to 80⁰C Extended: -40 to 125⁰C | 3.3 to 24Vdc, 4.5 to 15.4 Vdc 8 to 30Vdc | Up to 1A | |
![]() | Customer specific | Customer specific | Customer specific | Customer specific | Customer specific | Customer specific |