This is a calculator pencil made by Ruxton Multi-Vider of New York in 1929.  It is made of White / Ivory color Bakelite with 14-karat Gold filled trim.  This is called the Standard Model.  By design, it can multiply and divide.  By sliding side of pencil to desired calculation, answer is given.  Top cover is missing, but reveals a worn eraser inside.  Pencil has a black colored lead.  Included is a photo copy of 11 page directions.  This 81+ year old instrument is in good operational condition.  Collectors of engineering calculating and computing history memorabilia will find this a highlight.