's a great old piece of Police gear that was made by Federal Labs in Pittsburgh,PA. It was patented in 1925. Federal Labs were the makers of alot of police gear including tear gas guns, tear gas billys, as well as pens like these. I have had three of the billys, but I have never seen on of these pens; pretty cool.Federal Labs were such a lage manufacturer and distributor of police weapons and gear that they were the sole US distributor for Thompson Machine Guns. It is 5 3/16" long. The finish is at least 90% with some expected age thinning. The place of the trade mark is black, I had to get the light to reflect from it to get a readable picture. The pocket clip has Faultless USA. It looks like it was gold plated with most of he plating gone and some light brown patina replacing it, with a small amount of light rust. The pat number on the top is 1,772,656. The functions are fine. I'm not sure how to open it but I'm not sure one would need to at this point. A great old piece of Police history that would compliment any Police collection or if you specialize in Federal Labs stuff this piece looks to be pretty rare. Low start and NO RESERVE!!