A surveyor's tripod is a device used to support any one of a number of surveying instruments, such as theodolites, total stations, levels or transits.
The modern sturdy, but portable, tripod stand with three leg pairs hinged to a triangular metal head was invented and first manufactured for sale by Sir Francis Ronalds in the late 1820s in Croydon.
Materials for older tripods were predominantly wood and brass, with some steel for high wear items like the feet or foot points.
Leg lengths are adjusted to bring the tripod head to a convenient height and make it roughly level.
The flat surface of the tripod head is called the foot plate and is used to support the adjustable feet of the instrument.
The mounting screw is hollow and has two lateral holes to attach a plumb bob to center the instrument e.g. over a corner or other mark on the ground.