Check the listing for details. Vintage Keuffel & Esser Co Polyphase Slide Rule N4053-3 w/Case. Condition: Used. Listed at 24.00 USD. Vintage Keuffel & Esser Co. Polyphase Model N4053-3 Slide Rule and black case. The classic slide rule is in excellent condition and is made with wood, laminated face. The cursor is made of plastic and metal. One of the runners for the cursor have broken, which allow the cursor to come off the rule. The other runner has a crack. The reverse of the slide rule features U.S. Bureau of Standards conversion table. The case is also in great condition; research indicates the black case is made of leather. Wonderful gift for the collector. Made in the USA. Family Owned. Great item for the collector! Please carefully review photos and feel free to ask questions. Reasonable offers are welcome. Sold As Is. Shipping to continental US States only.