I've sold some in the past to customers who had large aircraft.
Mine come with a telescoping antenna, and a clear, acrylic 5" hex base, which I recommend for the larger aircraft. They come with swiveling heads, and magnetic tips, and extend from 7" - 22" in height.
I've also sold them with 3" and 4" bases.
The ones shown above have 4" bases, and are being used with Furuta jets that are about 1/180th in scale.
E-mail me at:
Topgungrav AT yahoo d0t com
if you want more info, or would like to purchase some.
I hope that helps.
Regards,
Rob