It consists of cylindrical spring housing with a plunger attached to the top of the spring. Penetration needle is attached to the other end of the spring housing. The plunger is graduated in 1 kg divisions, to a maximum capacity of 60kg, which can be read with respect to the top end of the spring housing. A set of six needle points with areas of 645, 323, 161, 65, 32 and 16mm2 are provided. Supplied complete in a wooden carrying case.
Consists of a needle having face area 3/10 sq.cm. and graduated at a distance of 25mm. The needles point is an integral part of barrel which houses a calibrated spring. The spring is confined in a sleeve. 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. Supplied complete in a leather carrying case. AS PER ASTM C-403