Spot On: The New Standard In Leverless Limit Switches


HSI Sensing introduces Spot On, a new line of leverless limit switches imagined from the ground up to sense farther and faster, and last longer than any competitive switch. The line utilizes reed switch technology, a rugged, field-proven sensing medium perfected by HSI over the last 50 years.

“Unlike other leverless limit switches, Spot On’s switching contacts are vacuum sealed in a controlled environment, and then the entire sensing mechanism is encased in epoxy,” says David Posey, HSI Sensing’s CEO and Chief Technology Officer. “It’s about the closest thing to fail-safe that we could engineer.”

This, coupled with the fact that Spot On has no moving parts, make it ideal for even the most extreme operating environments including fluid processing, and oil and gas. Spot On switches can also sense twice as far and twice as fast as any other switch in the industry, and because they can be activated by any ferrous metal — like a metal valve or automation arm — no magnet is required for operation.

The Spot On line of leverless limit switches includes four models designed to tackle a wide variety of applications. HSI can also provide solutions for customers whose specifications require special  wiring, housings, connectors, certifications, and more.


Headquartered in Chickasha, Oklahoma, HSI Sensing (Hermetic Switch, Inc.) is the innovative leader in the engineering and precision manufacturing of custom reed switch and sensor technology. The industry experts in solving problems for customers in challenging design applications, they also precision manufacture those solutions to ensure consistent, unmatched quality.

Since 1968 HSI Sensing, an ISO 9001:2008 and AS9100 registered company, has been the premier choice for custom and standard reed switches, proximity sensors, and other sensing technologies for an array of industries including fluid control devices, reed relays, implantable medical devices, aerospace, heavy equipment, communications, transportation, and more. Their products are used in a variety of applications including commercial and military jet engines, security systems, commercial lawn mowers, external defibrillators, implantable medical devices, space station equipment, animal tracking, and more.

HSI Sensing is a privately-held company wholly owned by the employees. For more information about HSI Sensing, please call 405.224.4046 or visit