We keep making the Recon Bag smaller and it keeps working. The Recon Micro is 4×5.5 and uses a unique fill that is semi-light and and reacts much like heavy sand without the downsides of using sand. The fill conforms to an obstacle and packs tightly together while the grippy surface of the bag locks it in. The carbon fiber base is arca only at this time but it is typically easy to convert picatinny to arca or to add an arca attachment plate to Mlok or Keymod slots. This system brings you the ultimate in compact stability without the need to put straps over your rifle. This is not a balance bag and is designed to allow you the stability to drive your rifle and control recoil.