Abstract: A kit for fitting a handwheel to a focussing control of a rifle scope is used to enlarge a focussing ring of the control, without having to remove the focussing ring from the control. The handwheel is secured by a headed bolt to a projecting stub shaft. The handwheel has a side plate supporting an outer rim that has a plurality of peripheral indentations to assist turning of the handwheel. The side plate has a central hole and a hub that projects axially from the side plate and defines a bore for receiving the stub shaft. The outer diameter of the hub is received within an outer end portion of the focussing ring. The hub has at least one abutment that co-operates with the stub shaft to inhibit relative rotational movement. A cap bolt extends through the hole to engage the stub shaft and secure the handwheel t the control.