This International Standard specifies the dimensions, materials and manufacturing requirements, and designation of collets for tools with cylindrical shanks and their corresponding holders and nuts. For non-standardized clamping devices, such as clamping devices specified in drawings, these holders can be agreed upon between customer and supplier.Form A applies where a clamping range of H10 is sufficient.Form B can be used for any application without lateral cutting load.Annex A specifies the values for AT3 tolerance and AT4 tolerance.