This International Standard specifies a method for the determination of fibre length distribution parameters, principally mean length and the coefficient of variation of length, for all-wool slivers and rovings. The method is not directly applicable to slivers made up of a blend of two or more fibres. Selection of the test specimen is effected using an auxiliary machine, called "mechanical grip"; it may be used on top sliver, on worsted drawing slivers and rovings, and on slivers from the semi-worsted system.