Our Big Mens USMC Boots Size 7-13, 14, 15 and 16 meet the United States Marine Corps Certification Standards. Our Large Size USMC Boots come in Narrow, Regular and up to EEEE - 4E Extra Wide. When it comes to Large USMC Certified Boots for Men, XLfeet is your one-stop solution. Few retailers care enough about Men with Wide and or Big Feet, let alone offer up to size 16 EEEE USMC Boots. At XLfeet, Fitting Extra Large Feet is no Extra Large Feat.