This is the HPI Replacement AM Crystal Set on 27 mhz Channel #A4. The frequency for this crystal set is 27.145. FEATURES: Direct fit replacement AM crystals INCLUDES: One receiver crystal One transmitter crystal COMMENTS: There is a yellow tag on the receiver crystal indicating what channel it is. The tag also indicates what frequency it is. Also available: HPIL0601 #A1 Brown 26.995 HPIL0602 #A2 Red 27.045 HPIL0603 #A3 Orange 27.095 HPIL0605 #A5 Green 27.195 HPIL0606 #A6 Blue 27.255 mlm 6.29.03 ir/jxs