This is a GIBSON PTTP-070, the so-called Lightning Bar tailpiece. It's a type of wrap-around tailpiece with octave compensation protrusions. Unlike vintage parts, the protrusion position for the 3rd string has been adjusted to match modern strings. I purchased this part separately and used it for a while, but I felt it didn't suit my guitar, so I removed it and kept it in storage. Searching for the above model number reveals information that it's made of aluminum, but the weight is approximately 72g, so it's likely made of zinc die-cast with nickel plating. Since it was actually installed, there are marks on the protrusions, the string contact points, and the stud contact points, indicating a certain degree of use. It probably won't be very noticeable when installed on a guitar, but please judge from the photos. The studs that came with the purchase are also included. These also don't attract a magnet, so they don't seem to be made of steel. For those with a Les Paul or SG Junior or Special, or other guitars with wrap-around bridges, how about trying a bridge replacement?