The RH BluePeg System is a removable, reusable relative humidity probe that is easy to use and easy to read. It complies with ASTM standard F 2170-11. The unique design of the probes allows for a one-hour quick-test, a 72-hour F 2170 test, or for long-term monitoring. The probes can be removed from the sleeves and are small enough to disappear below the surface of the slab, and can be covered by a protective cap between readings. Lignomat USA.