I've got the model D. It is pretty *cough* stiff, and was a bit of a challenge to get used to packing with. It's got to be positioned just right to be comfortable, and most harnesses or underwear don't seem to keep it in the right place. I eventually made a basic adjustable harness out of elastic. I don't generally pack with it in public-- I don't pass and, unless I'm in my slouchy jeans, it would be noticable to anyone minded to look. Though, I suppose, anyone minded to look deserves whatever they get.