20265B | 1/2" Drive x 13/16" Standard Length Impact

https://www.gpsocket.com/products/category.phtml/individuals_and_attachments/1_2/

This socket is designed for use on tamper-proof buffalo covers used by water and gas utility companies.
1/2" Drive 13/16" 5 point Utility (Buffalo Cover) Skt.  |  Poly Bag with Barcode  |  Weight: .28 lbs.  |  Lifetime Warranty