My experience with these shuttles is really bad, but I want to think that I just got a bad pack of shuttles. Very weak, they just got broken after some hits, and in one hour of "calm" non-smashing training I had to use 3 or 4. Take care.
When I steamed my HIT 700 1-2 days before use, the feathers lasted OK. But the cork is not of good quality, and speed is not very consistent. I think they are ok for training session with children who jsut started the sport, and for the price I got them (about GBP 6 per dozen), I am not expecting any miracle.