Smith & Wesson M1-1 Oversized Handcuffs [NIJ]
These are oversized Smith & Wesson handcuffs. Model 1-1. They accommodate a larger wrist size and also close smaller than average.
They sometimes require a more special larger case to fit them.
They have a pin-push double locking mechanism instead of the usual window slot one.
These are the more modern version which are riveted together and more capable of defending against being prised apart by seat belt buckles etc.