This part of ISO 8655 specifies – metrological requirements, – maximum permissible errors, – requirements for marking and – information to be provided for users, for dilutors with a sample uptake capacity (In) from 5 μl to 10 ml and a diluent capacity (Ex) from 50 μl to 100 ml. They are designed to deliver the sample and diluent together in measured proportion and measured volume. NOTE – General requirements and definitions of terms for piston-operated volumetric apparatus are given in ISO 8655-1. The gravimetric reference measurement procedure for the determination of volume is given in ISO 8655-6. Alternative methods for the determination of volume are described in ISO 8655-7. For safety requirements of electrically powered dilutors, see regional or national safety standards.