There are three types of precision runway CAT III:

(a) CAT III A: Operations are conducted or intended to be conducted down to a runway visual range (RVR) not less than 600 ft (no decision height (DH) being applicable).

(b) CAT III B: Operations are conducted or intended to be conducted down to an RVR not less than 300 ft (no DH being applicable).

(c) CAT III C: Operations are conducted or intended to be conducted with no DH and no RVR limitations.