Optimum antenna for large twins and medium jet aircraft. Only 8.25 inches high, yet provides good performance without the added drag of a taller blade-type communication antenna. Skydrol and rain erosion resistant. The CI 211 has been re-tested and upgraded to the new RTCA DO-160D environmental requirements and offers the 118 to 137 MHz frequency associated with DO-186 MOPS. Rated to 573 kts.