Theodolite security seals:

Theodolites are surveyor’s tools that measure both horizontal and vertical angles of a building which can also be used as a security seals. They are similar to transits, but have an optical magnifying system inside them that tends to provide somewhat more accurate readings of angles than those from a transit. As precise pieces of equipment that depend on internal telescopes to take measurements of the angle to a target, theodolites need to be maintained carefully and cleaned thoroughly between uses. Doing so will ensure the theodolite is ready to make accurate measurements as soon as you take it out of its case on the next job site. Use the theodolite’s sun shade to keep it out of direct sunlight. Temperature changes will skew readings. Expansion and contraction from heat and cold will also wear out the theodolite’s parts over time. Wipe the dust from both the metal and glass parts of the theodolite after each use. Use a soft brush for this.