Heavy Patch 4" Round, Good Colors with Iron-on Backing. NAVAL MOBILE CONSTRUCTION BATTALION NMCB 21. Great Detail and stitching - Great for a jacket or vest. VERY HARD TO FIND! Great Gift Idea for ANYONE. HatnPatch Is THE Veteran Owned and Operated Business - Retired Marine - We Ship Your Order Within 24 Hours And Usually The SAME DAY!