Prop is an infinitely reusable product used to support formwork shuttering. Its telescopic function allows speedy erection and dismantling without tools and it has no loose parts to be mislaid or lost. A threaded external tube in combination with an internal tube with intermediate holes gives the desirable extended size within the maximum and minimum extended range of the prop. Its a self cleaning stub on the collar nut, when rotated, automatically cleans the threads of dirt, cement and other foreign substances that hamper quick and easy adjustment. Simple insertion of a rod in the holed boss on the collar nut facilitates turning of the collar nut in confined spaces.