For determining the aggregate impact value of coarse aggregate. Consists of base weighing between 20-30 kg with a lower surface of not less than 30 cm and support columns to from a rigid frame work around the quick release trigger mechanism to ensure an effective free fall of the hammer during test. The free fall can be adjusted through 380 ± 5.0 mm. The hammer is provided with a locking arrangement. A metal tup(hammer) weighing 13.5 to 14.0 kg, the lower end of in cylindrical shape, 100 mm in diameter and 5 cm long with a 2 mm chamfer at the lower edge and case hardened. Complete with a cylindrical cup, 102 mm dia X 50 mm depth, one measure 75 mm dia X 50 mm deep and a tamping rod of circular cross section 10 mm in diameter and 230 mm long, rounded at one end. AS PER IS: 2386 (Part - IV).