buy voice amplifier

RFQ Details

I need to source a voice amplifier for use in our school classes, in our gymnasium and on our fields. I have seen some that can be put on your waistband or belt bag with a headset microphone and those are the ones I am looking for.
I am from New Zealand so you would have to be able to take credit card from here an ship it to me.
I am not looking at expensive ones just ones that would be useful for our purposes.
Thanks

Chris Patten