Quick answer: This is a pair of fins from Riffe.
For bigger divers, fin fit starts with the foot pocket. Size to the boot or bare foot you'll actually use, and look for a blade that matches your kick so you save air and energy.
Offered in 2 options, including 40/41 (6-7), 38/39 (4-5).
Size to the boot you'll wear, not your street shoe. Wide or high-volume feet should lean toward the larger size, and open-heel fins give you the most room to adjust. Read How to Choose Scuba Fins for Comfort and Power. More options: Fins for Wide Feet & Larger Divers.