SPX ( SPW) definitively agreed to sell its Kendro laboratory and life sciences products business to Thermo Electron ( TMO) for $833.5 million in cash. SPX, a Charlotte, N.C., industrial products company, said it expects after-tax net proceeds of $675 million, which it will use to pay down debt and buy back stock. The company said it acquired the business in its 1998 buy of General Signal, and it has expanded Kendro from a $75 million business into a $365 million one. Kendro designs and manufactures a wide range of laboratory application products for sample preparation, processing and storage -- including incubators, freezers, refrigerators, centrifuges and heat-treat ovens. In after-hours action, SPX rose 29 cents to $38.58. Waltham, Mass.-based Thermo Electron fell 7 cents to $28.58.