Yale 8013 Sash window locks have a threaded lock barrel which is fixed into the inner frame and the window is secured by locking the inner bolt into the barrel and frame using the key.
Can also be used in hinged windows. The locks simply screw into the barrel.
Yale 2 x Additional Keys Only for 8013 Dual Screw Window Locks . The additional keys are ideal to stored in a safe place in case of misplacement of the original key.