Naval Special Warfare Development Group. SEAL Team 6 / Six. Condition: Used, and in good shape. The coin is 2 inches in diameter, with epoxy on both sides. NOTE: Never personally given any of the coins. All coins are guaranteed to be in excellent condition unless specified above. The free listing tool. The item “Naval Special Warfare Development Group SEAL Team 6 Chiefs Navy Challenge Coin B” is in sale since Thursday, August 20, 2015. 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.