This second edition cancels and replaces the first edition (ISO 2415:1973), ISO 2731:1973 and ISO 2791:1973, of which it constitutes a technical revision. Specifies the characteristics, performance and critical dimensions necessary for interchangeability and compatibility with other components in a range of sizes having working load limits from 0,63 to 100 t, and in grades M(4), S(6) and T(8). In the case of dee shackles for use with forged steel lifting hooks it may be necessary to use an intermediate component to make the connection.