Most tourbillons use standard Swiss lever escapements, but some have a detent escapement. The detent, however, must be closely aligned with the threaded hole prior to fastening. Cooke initially made a telegraph with a clockwork detent mechanism operating electromagnets. If left powered at a final step a strong detent remains at that shaft location. The barrel is then returned into place and secured with a detent lock. The barrel was then returned into place and secured with a detent lock. A detent escapement has a strong advantage over other escapements as it needs no lubrication. The flip sight locks in position with a spring detent. It is also known as detent or 'no-current' torque. The tritium front post installs into the front sight base using a detent and spring. In France, 1748, Pierre Le Roy invented the detent escapement characteristic of modern chronometers. Other positions may have a detent to hold the position when released. With a larger detent interval, fewer images are needed to capture a complete panoramic scene.