We recommend a yearly recalibration cycle for all IST data recorder systems. IST provides a complete recalibration service to help keep your system providing accurate results. IST has been certified to MIL-STD-45662A. All IST calibrations are traceable to the National Institute of Standards and Technology (NIST) We request customers contact IST Technical support via e-mail, fax or phone to get an RMA number before returning equipment.