This is a rear fully adjustable sight, black target, for the Colt Pistol Model 70, 80 & 90 Series. This sight sits "Low Profile" and made to work with the original front sight on the pistol. The dovetail base width is approximately .320" on this series of sights. If this base is small for your dovetail you will need the 1911 A-1 version which is wider at approximately .330". This sight uses the original Colt stock front sight and sits low profile when mounted. Additional wrenches are included in the package. These are top quality LPA brand sights made in Italy. The rear sight is fully adjustable, for elevation and windage, so you may adjust it in any way to your liking to correct your pistols point of impact. The sight set is made of steel construction, not plastic. These sights use the original dovetails/slots on the pistol slide. These are the best sights on the market today to improve your pistols sighting