For 50mm bits or larger and bit tip holders, please note the following directions: If the bit is falling out of the driver, you may need to use more force when inserting the bit. First, put the bit into the driver and then press the bit against a hard surface, while pushing with the heel of your hand on the end of the handle. When doing this, you should feel a slight give or hear a little click signalling that the clip holding the bit has expanded in size. This clip will now hold the bit in place. To check that the bit is inserted properly, the bit should go into the shaft about 12.5mm. Additionally, if the bit does not fall out when the tool is turned upside down, the bit is inserted properly.