At 12:49 04 March 2011, John Smith wrote:
Am 04.03.11 13:01, schrieb Nigel Cottrell:
This looks a lot like the Trig 21 which I have had fitted in a
powered
plane for about 18 months and am very happy with.

http://www.trig-avionics.com/library/TT2xBrochure.pdf

The TT21 is a class 2 transponder and therefore *not* suited for
gliders. If you choose to go with Trig, then do yourself a favour
and
buy the TT22.
If you want a Class 1 the best option currently available is probably
the TT22.
Here in the UK the possibility of flight above 10000' is very limited
Wales, Scotland and a few areas in the North of England and so
wouldn't be a consideration for the vast majority of owners.