On 2 Nov, 10:17, Ian Strachan wrote:

With 43 types of recorders with
all sorts of different characteristics, it was becoming more and more
difficult to treat them all in the same way. Therefore, in 2005, IGC
introduced a series of different IGC-approval levels for ALL IGC-
approved recorders. These levels are listed in para 1.1.3.3 of Annex
B to the Sporting Code (also on the IGC web pages).

And that, my friends, is why I'm sticking with clockwork and silver
nitrate!

Ian