The sensing edge is for causing a closing door to open by actuation of a device upon force being applied to the sensing edge. It comprises a compressible outer sheath having a grooved wall surface and at least a portion of a switch assembly positioned within the sheath. The grooved wall surface renders the sheath more easily compressible thereby increasing the sensitivity of the sensing edge.It responds to obstructions in openings controlled by garage doors, rolling doors, rolling grilles or gates and signal motor operators. These edge devices are usually attached to the bottom edges of an upward acting door or grille or trailing edge of a horizontally moving gate. It provides a signal to an operator and does not itself control a door or gate.