Estadio Buzzer Flags

[HullRef]

Hi Guys
Just bought a set of estadio buzzer flags for a gcse electronics project and need to know the frequency the flags use. Anyone any ideas? Estadio have gone bust now so I can't contact them, could do with some help.
Thanks

 

[Southend-ref]

Can't help on that, but that's one way of convincing yourself to get electronic flags! How much were they?

 

[HullRef]

Only cost me £8 and all I have to do is build a receiver from scratch but I can't unless I find out the frequency. The flags are very poor quality though and that's taking into account that they were only £8. I've got better ones from sports direct!