Rare Naval Special Warfare Development Group DEVGRU SEAL Team 6 Silver Squadron TACDEVRON-5 Tier-1 Navy Challenge Coin #C298. 2 1/2″ x 2″ inches. This is one of most difficult DEVGRU coins to find and acquire. There is not an encrypted message on it, as the call sign letters on the shield are direct support functions. Thank you for looking! PLASTIC COIN STAND NOT INCLUDED. Please add any additional items to your cart.