NIST Traceable Calibration with Certificate & Measured Data for Graphtec GL860 Data Loggers with a specific terminal (For example, if a GL860 and two B-563 blocks are ordered, 2 calibration certificates are needed). Includes data. This item is NOT included with a new unit and should be purchased at the same time as the new unit. Shipping charges will apply if not ordered at time of logger purchase. Please allow 3 week lead time.