This Crystal Set fits the: R127DF, R127DP, R124DP, R128DF, R128DP, R129DP, R138DP, R148DF and R148DP. Crystal Sets - Ideal for replacements or frequency options. Each set includes both transmitter and receiver crystals. FM set replaces crystals in older Futaba systems. AM crystals available for 27 MHz or 72/75 MHz systems. Dual Conversion FM Crystal Set is for all Futaba DF or DP receivers.