Valley Forge & Bolt Data Logger. Use an SPC4® 406A meter to wirelessly measure and record bolt tension information for use at each maintenance cycle. Configure individual machines, flanges, and bolts for data collection. Store data for comparison to previous readings or for inspection requirements. Make notes in real time on individual bolts which can be reviewed at the completion of the session or in the summary. Display results in either line or spider graphs or as raw data. You can even export your results.