The following diagrams illustrate the components and features of the Echo J7:
The distance (gap) between the magnet and sensor must be within 4mm (1/6 inch) to trigger the signal. echo j7 cycle computer manual
: Compatible with ANT+ and Bluetooth sensors for heart rate, cadence, or power monitoring, and can sync with apps like Strava. Setup and Calibration or power monitoring
I searched for an official but could not find a complete, publicly available PDF or document. Echo is a brand that produces budget-friendly cycling computers (often sold on Amazon, AliExpress, or eBay), and the "J7" appears to be one of their basic wired/wireless models. Manuals for these devices are typically included in the box or provided as a small paper insert. echo j7 cycle computer manual