computermonkey,
The blue Control horns was shipped with my Oxai (now Hui Yang F3A) Galactika plane. They can be bought via a Hui Yang F3A reseller.
However these blue Control horns can be bought for example from this Japanese hobby shop, Morris-Hobby:
NTSƒxƒAƒŠƒ“ƒOƒz[ƒ“iVŒ^j
It is actually Narutech Service (NTS) that make them, at least they are marked NTS on the plastic bags as You can see if You click on the image in above link.
They are very nice and good qualtity horns, it is a small ball bearing on them.
Morris-Hobby has many nice accessories for RC and F3A. Just click around on their site and Yoy will see.
/Bo