not sure mine is the dynamic one - that has D cheeks doesnt it? but i have the sprenger kk ultra...conrad i think and its fantastic. horses really do go so well in them!totally worth the price, my horse is incredibly difficult to bit and seem to be permanently changing bits because he works out how to get away from it, whether its leaning, dropping behind it, or just chucking his head around, and i spent the summer in the kk-which is the longest ive ever kept the same bit in...he was totally happy with it - untill he worked out it was only a snaffle!haha!!friend bought a nule schule (sp??!!) one last week - i cant spot anything different, apart from the price! think they're practically identical and apparently shop4bits (i think its that anyway) will let you have a trial period of 2 weeks!dont quote me on it though!good luck!