The Irwin Phillips insert screwdriver bits are engineered for use in hand-driving applications or with power tools. They are designed for use in an insert holders with C-clip for retaining ring notch. The bits are compact and versatile with a 1/4 inch hex body and made from high grade S2 Steel with a titanium coating. The Irwin IRW10504333 Screwdriver Phillips bits come in a pack of 2 with the following dimensions PH2 x 25mm.