the most distinctive tool of erectus was the acheulean hand axe, first invented 1.8 million years ago (mya). this hand axe was made by chipping a suitable stone with a hammer stone. later, the neanderthals used a soft hammer made of deer antler bone to make better tools. the acheulean hand axe lasted for over a million years as the main tool. its main use was for butchering meat. this we know because different uses leave different micro-wear on the hand axe surfaces.