These are available with either an international standard (IS) six-bolt disc or with the Shimano compatible C/Lock splined interface for use with a Shimano splined interface hub.
The front calliper fits both IS and post mount forks (it comes with the mountings), and the rear calliper fits IS mountings only. Its stopping power is far better than a rim operated brake and it gets better with use. We found that the brake took around 50 miles to bed in, during which time they squeaked a bit, but after this period performance was noticeably sharper and required less pressure at the lever. Beware that where mounted at the rear of the bike, the calliper can foul some rack stays if fitted.