Excerpt From DA PAM 670-1, Paragraph 20-3
A. Boots, combat, tan, leather. The Army combat boots (HW and temperate weather) are clothing bag issue items.
The two types of issue Army combat boots (HW and temperate weather) are made of flesh-side out cattlehide leather with a plain toe and tan outsoles. Soldiers are required to possess two pairs of issue Army combat boots (HW) and one pair of issue Army combat boots (temperate weather) (specification) boots.
(a) The issue Army combat boot, HW, is made of tan-colored, flesh-side out cattlehide leather and nylon duck upper, removable cushioned insert, a closed loop speed lace system, and drainage eyelets.
(b) The issue Army combat boot, temperate weather, is made of tan-colored, flesh-side out cattlehide leather and nylon upper, a weatherproof-breathable membrane with limited flame resistance, conduction heat resistance and liquid fuel penetration protection, removable insert, and a closed loop speed lace system.
(2) How worn.
(a) The boots are laced diagonally with tan laces, with the excess lace tucked into the top of the boot under bloused trousers or slacks, or wrapped around the top of the boot. Metal or plastic cleats and side tabs are not authorized for wear. Sewn-in or laced-in zipper or Velcro® inserts are not authorized.
(b) Rubber or pure polyether polyurethane soles are the only outsole material that currently meets the need for durability and traction on surfaces in multiple environments and temperature ranges. Other materials (that may be of a lighter weight) may have significant problems in these areas.
(3) Optional boots.
(a) As an option, Soldiers may wear commercial boots of a design similar to that of the Army combat boot (tan), as authorized by the commander. The boots must be between 8 to 10 inches in height and made of tan flesh-side out cattlehide leather, with a plain toe and a soling system matching the color of the tan upper materials. Rubber and polyether polyurethane are the only outsole materials that are authorized. The soling materials will not exceed 2 inches in height, when measured from the bottom of the outsole, and will not extend up the back of the heel or boot or over the top of the toe. The exterior of the boot upper will not contain mesh but will be constructed of either all leather or a combination of leather and nonmesh fabric.
Soldiers may wear optional boots in lieu of the Army combat boot (tan), as authorized by the commander; however, they do not replace issue boots as a mandatory possession item.
(b) Optional boots are not authorized for wear when the commander issues and prescribes standard organizational footwear for safety or environmental reasons (such as insulated boots or safety shoes). Personnel may wear specialty boots authorized for wear by specific groups of Soldiers, such as the tanker boot, only if the commander authorizes such wear. Soldiers may not wear optional boots in formation when uniformity in appearance is required.