This aggregate classification system uses a HM-925 Thickness Gauge for determining flakiness index and a metal HM-926 Length Gauge for determining elongation index. Aggregate is separated into seven sieve fractions from 63—6.3mm, and each fraction is evaluated separately.

HM-925 Thickness Gauge has seven labeled slots for rapid hand trying of particles from each of the seven sieve cuts. The mass of all flaky particles as percent of the sample is the flakiness index. Thickness Gauge is enameled sheet metal with clearly marked sieve fraction ranges for each slot. Est. Ship Wt.: 3lb (1kg).

HM-926 Length Gauge has six labeled openings between pairs of metal pins for measuring length of particle from each of the six sieve cuts below 50mm. The mass of all elongated particles as percent of the sample is the elongation index. The Length Gauge has stainless pins set in a brushed aluminum base stamped with sieve fraction ranges between pins. Est. Ship Wt.: 3lb (1kg).

Test aggregates must be sieved using sieves with openings of 63, 50, 37.5, 28, 20, 14, 10, and 6.3mm. These are available separately (listed elsewhere) as 200mm diameter brass frame sieves with stainless steel cloth as International Test Sieves.