A 15 Piece heavy-duty Impact Driver Set in a robust oil resistant case. When used in conjunction with a medium sized hammer an impact driver will loosen or tighten stubborn screws & bolts. Contents:: 12 x Impact bits 6 x 36 Flat 8 x 36 Flat 10 x 36 Flat 12 x 36 Flat PH1 PH2 PH3 PH4. 4 mm. Hex 5 mm. Hex 6 mm. Hex 8 mm. Hex. 1 x 1/2 in. Drive heavy-duty reversible impact driver. 1 x 1/2 in. Drive impact coupler adaptor. 1 x Hex x 3/8 in. male adaptor.