ID: 
2538
Maker's Name: 
Weston Electrical Instrument Corp.
Where made: 
USA
Dimensions: 
15.5 × 3.2 × 5.8 cm

Two Weston shunts and two from an unknown source.

Shunts are used to increase the range of an ammeter by diverting most of the current around it in a controlled way.

See markings on 5A shunt.