Breitling, Geneve, Ref. 1577, Chrouoslide regle a calcul, made in the 1970 's. Chromium plated decimal and duo-decimal counter with tachometer, 30 minutes recorder, retour en vol and a circular slide rule. Three piece, "variee" polished with black revolving bezel. Black painted with Arabic 10 minute decimal and duo-decimal chronograph rings, outer ring, inner tachometer scale, subsidiary 30 minutes register. Circular slide rule adjusted by means of the revolving bezel. Black and white painted hands.