Consists of a needle having face area 3/10 sq. cm. and graduated at a distance of 25 cm.
The needles point is an integral part of barrel which houses a calibrated spring.
The resistance offered by the concrete mortar is shown on the direct reading scale with a marker ring which holds its position when released.
Scale range is 0-50 kg/cm2 when the penetration resistance reaches a value of 35kg/cm2 the concrete is assumed initially set.
The spring is confined in a sleeve.
Supplied complete in carrying case.