brass and steel tool; main tool is brass cylinder with extendable rod at one end. 17 brass and steel circular attachments which attach to the main tool (one missing). Graduating in size; long handles and a central protruding cylinder at base. Attachments are numbered on handle. Marked on tool and attachments: "SWISS". Kept in a rectangular back leather box with black velvet interior. Sticker on outside of box: "H.M. Conway & Co. Ltd. / WELLINGTON . N.Z."

Having removed a mainspring from its barrel for cleaning or replacement, it was difficult to rewind the spring into the barrel without causing damage or distorting. Many different types of mainspring winders were invented, one of the more satisfying types, like this one, having many sizes of barrels, ranging from the smallest wrist watches to pocket watch size. The spring was first wound into a slightly smaller size of barrel, and then transferred into the watch's barrel.