Naval Special Warfare Group 4. Special Boat Team SBT-22. Dirty Boat Guys / DBG. Condition : Used and in nice shape. This coin is approximately 4 inches wide by 1 1/4 inches high. This item is in the category “Collectibles\Militaria\Current Militaria (2001-Now)\Original Items\Challenge Coins”. The seller is “rolyat11″ and is located in this country: US. This item can be shipped worldwide.