Bungie give the activity a title, increase the tokens and add Iron Engrams to bounties which can be decoded into weapons or armor from Lord Saladin. Iron Engrams work the same way as umbral engrams but are only available during IB. Completing daily bounties for IB rewards one Iron Engram. 4 per day Weekly bounties give two Iron Engrams Tokens can be exchanged into 1 Iron Engram Etc.