Sensor Testpak ifm efector E18401The Sensor Testpak E18401 from ifm is compatible with most 24V DC sensors. Has 4 terminals for fault testing, as well as teach inputs. Sound alarm for signal detection. Thanks to the compact and portable design, the E18401 sensor Testtpak is ideal for testing or teaching sensors on the go in many automation applications. Uses 6 AA batteries to produce voltage (not included).