Bit #3 is for larger screws that sometimes require more torque. I use them with effect. I tend to go for the cheaper models #3. They have been well tested (actually just one of the five bits). I'm still rocking my first beat in about 2 months. For me, this is everyday use. I haven't had a serious side rib stump yet, for most screws I work with it fits perfectly. Well done, kudos to Bosch!