Klipsch Reference Series Owner's Manual page 19

RF-7 II RF-42 II RF-52 II RF-62 II RF-82 II
RB-41 II RB-51 II RB-61 II RB-81 II RS-41 II RS-42 II RS-52 II RS-62 II
RC-52 II RC-62 II
RC-42 II
RC-64 II