This is a nice vintage KEUFFEL & ESSER CO. N.Y. slide rule, model number; Marked "4054", 10.25 inches long,  Backside is with a plastic inset label of equivalents information. It is in very good used condtion, clean, minor age darkened stains; no cracks or chips - no owner's names or marks; indicator slides smoothly as does the center rule. Scales onon the back are S, T. Comes in original case with black leatherette covering; good condition, some wear but still fairly solid;  One side is marked "KEUFFEL & ESSER CO FAVORITE SLIDE RULE". A very handsome, quality made rule in it's day!