This is the tiny little pin that goes into the end of the assembly screw (take down screw) on the Winchester 1890 - 1906, mod 62 and also fits the 63 and 1903 models. Many a person has been frustrated because they did not know they had to take the pin out before completely removing the takedown screw :-) The purpose of this pin is to keep the takedown screw in the receiver when it is loosened to break the rifle in half so the takedown screw does not fall out and get lost. The pin come a little long for ease of handling. They also have a temporary pink coating so they are easier to see. You may laugh, but when you drop this little sucker you will be glad its pink! The color is usually worn off by the time the install is done. When you install it into the hole in the end of the take down screw, you will have to take a little file and remove some of the length of the pin so it fits into the bushing. Or you can use a pair of snips or the grinder to take it down to 1/4 inch prioor to install (this is where you usually loose it though :-)