All covermeters have different measurement probes to measure the full range of concrete
covers, either by using a universal probe with different probe settings (low or high range) or by using two different probes (deep or shallow). In the over lapping range where both probe settings could measure concrete covers, the measured covers by different probe settings do not match. Manufactures recommend that high range setting should only be used if the concrete cover could not be detected when the probe is set to low range.