RC Crystals usually come in pairs including one Tx for the Transmitter and one Rx for the receiver

In RC these 4 bands are the most commonly used for rc crystals:

27mhz AM
27mhz FM

35mhz FM

40mhz FM

72mhz is not legal in the UK

Will these rc crystals work with my RC and Receiver?

To find out remove your previous transmitter rc crystal.

Their usually will be something along the lines of 27.045 AM written on it.

The first two digits is the important part as it represents (for example) 27mhz.

The last two letters represent the band your RC is on.

The last 3 digits can be different to what you have already but the other parts must remain the same.

Most rc crystals with 27mhz AM written on it will fit that particular radio and receiver.

Where else can it be found?

If not written on the rc crystal itself then it could be found:

• on a sticker along the bottom of the RC
• or on a small round sticker on the receiver box lid
• or finally in the manual.

Can I use two models on 27mhz AM at the same time without the interfering?

Yes if the last 3 digits are different, for example 27.045 and 27.095 will work together without interfering. 

However two rcs on 27.095 wont.