Feeler Gauges for Working at Height Here at Secure Tools, we stock feeler gauges for working at height safely. Designed to deliver exceptional accuracy in small areas, feeler gauges are the ideal tool for measuring the width of small gaps, particularly in tight spaces where other common devices, such as a measuring tape, cannot fit. Featuring several metal strips attached to a central hinge, our feeler gauges can accurately measure gaps or clearances between parts between .05 – 1mm. Furthermore, this stainless-steel central hinge also doubles as a permanent attachment point, letting you tether the tool safely to your harness and prevent accidental droppages when working from height