Naval Special Warfare Development Group. SEAL Team 6 / Six. Condition: Used, and in good shape. The coin is 1 3/4 inches in diameter. NOTE: Never personally given any of the coins. All coins are guaranteed to be in excellent condition unless specified above. The item “Naval Special Warfare Development Group SEAL Team 6 Chiefs Navy Challenge Coin” is in sale since Friday, September 21, 2018. This item is in the category “Collectibles\Militaria\Current Militaria (2001-Now)\Original Items\Challenge Coins”. The seller is “rolyat11″ and is located in Panama City, Florida. This item can be shipped worldwide.