Adaptor base and circular cutting guide for the 400/420 jigsaw range. The circle cutter has a centring pin and tape measure fitted so that you can set the circle diameter or arc accurately from 68mm – 3m. Revolve the jigsaw around the centre pin for a fast and precise smooth cut. The adaptor base simply clips to the 400 range of jigsaws via a quick release mechanism. KS-PS 400-Set.