A hammer includes a handle and a head. The email filtering system analyzes the email to determine whether it is spam, phishing or contains a virus and sends it back to the local gateway device along with the filtered determination. Power is applied to the receiver substantially only corresponding in time to the timing of the data bursts. Since the locking pin has a diameter which is larger than a locking hole in a shaft by about 0. The measurement data are processed with the correction data in a realtime kinematic positioning engine to obtain a position estimate for each of a plurality of epochs.