At first blush, Mafell's NFU 50 appears to be a regular track saw. Then you see its beefy cutter head: That thing is 60mm (2.4") wide! And it can cut nearly 2" deep. It's meant to be used by timber framers, to cut tenons on large timbers, for instance. It can also be angled, and used to cut bird's mouths on rafters. See it in action: