Gurley Precision Instruments, or GPI, is an ISO-9001 certified U.S. manufacturing company based in Troy, New York.
During the Cold war era, Gurley manufactured gyroscopes, sextants, star trackers, theodolites, angle dividers, optical positioning systems, and various other precision guidance devices for guided missiles and for space launch vehicles.
The W. & L. E. Gurley Building in Troy was named a National Historic Landmark in 1983.
The Gurley second or Gurley unit is a unit that describes air permeability as a function of the time required for a specified amount of air to pass through a specified area of a separator under a specified pressure.
Specifically, it is defined as the number of seconds required for 100 cubic centimeters (1 deciliter) of air to pass through 1.0 square inch of a given material at a pressure differential of 4.88 inches of water (0.176 psi)(ISO 5636-5:2003).