These solid brass hinges are widely used for drop-leaf tables.
They perform the same basic function as a back-flap hinge, but one leaf is wider than the other so that it bridges the hollow member of a joint.
The knuckle is fully inset. Sizes given are height by open width.
The 1 1/4” × 2 1/8” hinges require #5 screws; the 1 1/2" × 2 7/8” hinges require #6 screws. (not supplied)