At the pre-opening bell, the frontline index S&P BSE Sensex opened in green with a gain of 112.46 points or 0.14%. On the sectoral front, metals jumped 0.25%, power zoomed 0.46% and auto soared by 0.18%. Meanwhile, Jain Irrigation Systems Ltd, KIOCL Ltd and Ambuja Cements Ltd emerged as the top gainers of BSE in the pre-opening session today.