This adapter converts a T-Rex to be compatible with tripods with a 3/8" centre bolt. The adapter replaces the bottom piece of the T-Rex using the same bolts and then allows the T-Rex to be bolted to heavy duty tripods with a 3/8" centre bolt.
$100 posted in Oz.
Which is a bit cheaper than APM:
http://www.apm-telescopes.de/en/moun...d-adapter.html