Abstract: A surveyor's levelling staff which comprises an endless graduated band or strip on a hollow elongated body with a portion of the strip to be viewed extending along a longitudinal face of the body and the remainder of the strip disposed within the body. The strip passes around a spring-loaded tensioning roller and a winding and brake roller inside the body. The tensioning roller maintains a predetermined tension on the strip and the winding and brake roller includes a winding handle to move the strip along the longitudinal face of the body and through the body, and a brake which, in the locked position prevents relative movement of the strip.