That's an early 914 front caliper. Basically made off the same casting as the 911 rear calipers with the fluid inlet on the back and not the side and, with a 42mm piston vs the 38mm variety on the 911.
These have standard hex head M7 fasteners vs. the Rive versions on the 911 caliper.
They will only work with the early 914 rotor offset.