Used exclusively on the Design Lab Equinox model, the lug bolts don't go through the hoop itself. Instead they go through mini "claws" which go over the hoop and pull it down to tension it. Gives the snare a longer sustain and a "retro" feel but it does make it more awkward to get a consistent rimshot or cross-stick. To be honest, they are bit "marmite*"

*For non-UK readers - you'll either love them or hate them.