In bipolar percussion the objective piece of toolstone is placed on an anvil stone, and then the percussion force is applied to the tool stone. Like projectile percussion, the tool stone is likely to shatter, rather than producing a single flake. Unlike projectile percussion, the technique has some degree of control to it. Bipolar percussion is not popular with hobbyists, but there is evidence that bipolar percussion was the preferred way of dealing with certain problems. Bipolar percussion has the benefit of producing many sharp flakes, and triangular pieces of stone which can be useful as drills. Bipolar percussion also does not require the manufacturer to locate a platform before setting to work, and bipolar percussion can produce sharp flakes almost the size of the original piece of tool stone. The lack of control makes bipolar percussion undesirable in many situations, but the benefits mean that it often has a use, especially if workable material is rare. Bipolar percussion is often used to break open small cobbles, or to have a second chance with spent lithic cores, broken bifaces, and tools that have been reworked so much that it is impossible to make further useful tools using traditional lithic reduction. The end result of bipolar percussion is often a big mess, with only a few pieces that can be useful as cores or flakes for further working, but if other methods would result in a total dead-end, bipolar percussion may be desirable.