Single Finger Knuckle Duster SFK 01 Purple Anodizing Type 2

Dimensions:
Material - Aerospace Aluminum
Coating - Type II Purple Decorative Anodizing
Height - 2 3/64" (52 mm) 
Width - 1 15/32" (37 mm) 
Thickness - 43/64" (17 mm) 
Finger hole diameter - 1" (25 mm) 
Weight - 2 oz (56 grams)

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

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