Box swivels, brass, for angling / fishing; common in 1800s to early 1900s.

Anatomy of a 100 year old tackle box

For the Love of History: September 2013

Net sinkers hi-res stock photography and images - Alamy

Historical Fishing

Brass Fishing Swivel

1900s Victorian Antique Mounted Fishing Reel, English, Brass

Fishing Devices and a short history of the Sport - Sharon Lathan

Anatomy of a 100 year old tackle box

Anatomy of a 100 year old tackle box

1900s Victorian Antique Mounted Fishing Reel, English, Brass

Vintage Tackle Blog

Brass Fishing Swivel