ZHIDA Autofeed Collate Screwdriver Gun Bit 146MM PH2 for Bosch MA55 3 PCS Top quality driver bits made in special alloy steel, hardness HRC 61-62, better than normal S2 steel. Total 146mm length compatible Bosch MA55 Autofeed Collated Drywall Screwdriver Gun, Bosch SGH182, SG450 and SG250 compatible. Exclusive torsion design extended service life three times less. Made in precision CNC milling machine, fit phillips #2 screw very well. Manufactuer of screwdriver bits, made in client s samples or drawing available. Size: H1/4x146x5.0xPH2