The Al-Plastic Multi-Cap corresponds to ISO standard is mainly used for injection containers (including elastomeric closures), And The caps shall be classified as follows: Type OB: Aluminum cap with central opening, and without overlapping plastics component; Type OD: Aluminum cap with complete tear-off tab, and without overlapping plastic component; Type ZB: Aluminum cap with central opening, and with overlapping plastics component; Type ZD: Aluminum cap with complete tear-off tab, and with overlapping plastic component.