Cut around spot welds without drilling through both layers of metal. The 3/8in. arbor has an adjustable pilot to set depth of cut to prevent weakening lower panel. Long-lasting, heavy-duty cutters have three large cutting teeth. Tool shaft is hex-shaped so it won't slip in your drill chuck (limit is 900 rpm). Tool comes with 3/8in. cutting head. 1/2in. cutting head (#19052) is available separately.