TBTYNB-1B is used to assess the durability of rock to weakening & disintegration when subjected to the simulated effects of climatic slaking. The rock specimen are dried and submitted to wear stress inside mesh drums which are rotated & immersed in water over a period of time. The test is performed times and the wear is expressed by loss weight of specimen. The equipment comes complete with a motor drive unit mounted on base plate which revolves two stainless-steel drums of Ø140x100 mm with of 2mm mesh.