Two Finger Knuckleduster DFK 01 Blue Anodizing Type 2

Dimensions:
Material - Aerospace Aluminum
Coating - Blue Decorative Anodizing Type II
Height - 2 11/64" (55 mm) 
Width - 2 13/32" (61 mm) 
Thickness - 43/64" (17 mm) 
Finger hole diameter - 1" (25 mm)
Weight - 3 oz / 90 grams

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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.

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