Littelfuse – Firecracker Press-Fit Reed Sensor and Magnetic Actuator for Position and Limit Sensing in Appliances, Security Systems and Industrial Equipment

The 59040 Series press-fit reed sensor is the first Firecracker reed sensor from Littelfuse with crush ribs on the capsule and requires no attachment accessories for installation.

This magnetically operated sensor is designed to press-fit securely into a 3/8” (9.5mm) diameter hole and offers another sensor option for the competitive reed sensor market. Its enhanced sensitivity allows for a wider air-gap between the sensor and its matching 57040 actuator. It offers three contact options: normally open, normally closed, and change-over contacts. It is a UL Recognized Component and offers switching capability up to 200VDC/140VAC at 10W/VA.

Typical applications include position sensing in appliances, door/window position sensing in security systems and limit sensing in hydraulic cylinders.


  • Magnetically operated press-fit proximity sensor
  • Cylindrical capsule with retaining ribs
  • Press-fits into a standard drill size hole of 9.5mm (.375”) diameter
  • Operates and mounts through non-ferrous materials such as wood, plastic or aluminum
  • Hermetically sealed contacts
  • Customer-defined sensitivity options available
  • Custom cable length and connector options available


    Position and limit sensing in:

  • Appliances
  • Security systems
  • Industrial equipment


  • Ribs on capsule compress when inserted into a mounting hole and provide retaining force, allowing simple and secure press-fit installation
  • Quick and easy press-fit installation that requires no screws, brackets, nor glue
  • Well suited for usage in high-moisture and contaminated environments
  • Non-contact solution, aesthetically more appealing than push-button or lever mechanical-type switches
  • Ideal for battery-powered applications because the contacts do not draw power when in the non-activated state
  • Reed contacts last for millions of operating cycles under microcontroller voltage and current logic-level loads