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.