Masons hygrometer - spirit filled is a wall-mounted wet and dry thermometer for determining the relative humidity. The mason's hygrometer measures the wet and dry temperature over the range of -15 to +50°C.

The masons hygrometer is supplied with a slide rule for calculating the relative humidity over the range of 1 to 97% RH.

The masons hygrometer housing is manufactured from robust white ABS plastic and incorporates an integral hook for wall-mounting. The case dimensions are 34 x 75 x 310mm.