A power tool includes an impact damping mechanism for damping an impact in a direction of rotation of a speed reduction mechanism portion 8. In addition, respective raceway surfaces of an outer ring and the inner ring and the rolling contact surfaces of the tapered rollers are crowned and are set such that a total crowning amount is 50 \u03bcm or larger, an outer crowning rate is 40% or larger and a roller crowning rate is 20% or smalled. The jaw member comprises a pair of elongated arms, a first arm and a second arm, which are joined together at a connected end. A compression module within the codec then compresses the scenes using the automatically-selected compression methods, after which an output module delivers the compressed scenes to the destination system with an indication of which compression method was used to compress each scene. In response to determination of the appropriate upgrade path, a version specific program upgrade component and a version specific upgrade program are associated with the determined upgrade path.