An extra long caliper brake set. Nutted version. Dual pivot design would be a significant upgrade over bikes fitted with single pivot brakes. Commonly used on cruiser bikes, or suitable for downsizing wheels on your existing bike, e.g 700c to 650b.
The drop range is 71mm to 91mm.
If used for more spirited rides, I would suggest swapping out the pads for some salmon Kool Stop pads.