This International Standard specifies the principal dimensions, tolerances and designation of drop wires for mechanical, electromechanical and electrical warp stop motions for weaving machines. This International Standard applies only to drop wires suited for Uster and Reed Chatwood automatic drawing-in systems. These drop wires are always closed with U-shaped thread eye and are distinguished as follows: a) for mechanical and electromechanical warp stop motions — M1 (for the Uster drawing-in system) — M2 (for the Reed Chatwood drawing-in system) — M3 (for the Uster and Reed Chatwood drawing-in systems) b) for electrical warp stop motions — E1 (for the Uster drawing-in system) — E2 (for the Reed Chatwood drawing-in system) — E3 (for the Uster and Reed Chatwood drawing-in systems)