The Shermans of the 4th and 5th Tank Battalions represented the lessons learned from past Marine battles in the Pacific. Extra track welded on the turret and hull, sand bags on the hull deck, wood and concrete side armor all to protect against Japanese magnetic Anti-tank mines and satchel charges. Cages or nails welded to hatches to get a dead space between the hatches and satchel charges so that the hatches wouldnt hurt the crewman under them. A water barrel mounted on the rear deck to give infantry water. An infantry phone on the left rear in a canvas bag so that infantry troops could tell tank crews were the target is. The Target clock enables new infantry to relate the target to the tank crew.