One of only 205 total produced in 1908 for use by the four Army units assigned to put the then-experimental Colt Model 1907 pistol through its paces, with the markings on this holster identifying it as one of the 65 sent to Manila Ordnance Depot in the Philippines for use by Troop K, 10th Cavalry. In addition to providing critical input on the design and use of .45 ACP pistols, which would shape the final design of the timeless 1911 pistol, these tests also revealed important ergonomic concerns with holstering said pistols, leading to the abandonment of the left-handed crossdraw typical of American martial revolvers in favor of the right side strong-hand draw which became near universal among the American military even to today. Constructed from 4 sections of brown leather (flap, belt loop, main body and base plug), the belt loop bears the stamp "ROCK ISLAND/ARSENAL/1908" above faded inspection initials, while the top edge of the flap is stamped "K 10 CAV'Y/No 27" above the embossed oval "US" stamp. The flap engages a fixed brass stud mounted on the main body, and the base of the main body has a teardrop shaped plug mounted with a brass lanyard ring, with a small drainage hole just above the plug. A steel reinforcement plate is present on the inside of the flap. These holsters were originally manufactured about an inch longer than necessary to fit the Model 1907 pistol, and many examples, not including this one, were later altered by shortening the body. Two other examples, one unaltered and the other altered, are pictured on pages 244-245 of "U.S. Military Holsters and Pistol Cartridge Boxes" by Edward Scott Meadows.