Specifications:

4 inch bare metal

6 inch bare metal

4 inches, one electricity, one charge (US regulations)

4-inch two-power one-charge (US regulations)

4 inches, one electricity, one charge (European standard)

4-inch two-power one-charge (European standard)

6 inches, one electricity, one charge (US regulations)

6-inch two-power one-charge (US regulations)

6-inch two-power one-charge (European standard)

6 inches, one electricity, one charge (European standard)