Vintage Signed Ketcham McDougall Retractable Chain Pin

This is a vintage chatelaine type chain pin for a pen, pencil, watch, keys, etc. from circa 1950's.  A chain pulls out and extends to about 14 3/4" long and then retracts. It has a loop on the end of the chain to hang whatever you wish. It has a secure "C" clasp closure,  It is signed on the back:  Ketcham McDougall, East Orange, N. J.   It measures 1" in diameter, and is in very good working condition.  I remember my teacher wearing one of these on her dress with a retractable mechanical pencil or pen attached.  I have also seen one on its original card marked "Key Keeper.  It could be fastened to the inside of a woman's purse for easy access to her keys.