Two Finger Knuckle Brass DFK 01 Sandblasted Copper

Dimensions:
Material - Copper
Finish - Sandblasted
Height - 2 11/64" (55 mm) 
Width - 2 13/32" (61 mm) 
Thickness - 43/64" (17 mm) 
Finger hole diameter - 1" (25 mm)
Weight - 10 oz / 280 grams

More similar products you can find here:
best copper edc knuckles near me in the USA

Special holes allow you to use this product as a Keychain. 
You can also thread a paracord (550-type) lanyard through the holes.
Nice gift for Him.

EDC-Craft-Store official website is the best place to buy original EDC-products at manufacturer's price.