Bosch T121BF3 3-Piece 3-5/8 In. 12 TPI Speed for Metal T-Shank Jig Saw Blades For medium to thin metals 1/4 In. to 1/8 In. thick (ferrous and non-ferrous) 21 TPI with unique tooth geometry including rigid and aggressive profiles for unrivaled speed in metal cutting Backward taper design simulates pendulum motion to increase speed Bimetal construction for durability and long life 3-5/8 In. overall length, 2-5/8 In. working length