Protimeter Humidity Box BLD4711 can be used with either the MMS2 and Hygromaster 2 meter in order to take surface relative humidity readings (%rh) to be taken on concrete floor and wall slabs. The yellow foam humidity box is placed on the floor surface and a Hygrostick is then inserted into the hole on the side. When connected via an extension lead which ports onto the hygrometer, the Hygrostick then provides the relative humidity reading of the cavity within the box on the screen of either the MMS2 or HygroMaster 2.