Lucas Power and Control Ltd.
- Supply proximity switchs, optical switches, ultrasonic, inductive and sonar sensors. Includes product features and specifications.
- http://www.lpc-uk.com/siemens/sensors/main.htm

SNT Sensortechnik AG
- Supply ultrasonic proximity switches and level detectors. Includes product applications and technical data in pdf format.
- http://www.sntag.ch/englisch/proximity_e.htm

Banner Engineering Corp.
- Manufactures integrated line of photoelectric sensors and machine safety products. Features new products, buy online, list of sales offices worldwide, and data sheets.
- http://www.bannerengineering.com/

Senix Corporation
- Manufacture ultrasonic distance sensors for machinery and industrial automation including motion and loop control, liquid and solid levels, and proximity sensing. Includes applications and technology.
- http://www.senix.com/

Migatron
- Manufacture ultrasonic sensors. Features product data sheets, applications, and capabilities. Includes an ultrasonic technology overview.
- http://www.migatron.com/

Hyde Park Electronics Inc.
- Manufacture a range of ultrasonic sensors and transducers. Features product specifications, applications, and a distributor locator.
- http://www.hpsensors.com/

Baumer Electric
- Manufactures a range of sensors including inductive, capacitive, photo electric, and ultrasonic. Includes product catalog and data sheets.
- http://www.baumerelectric.com/