Mossberg 500 500AT 12 ga Trigger Assembly Housing Pin OLD STYLE. This pin is needed to mount the Old Style Mossberg trigger assembly to the receiver. There are not many of these left around, and this is the only one for sale on the store at the time of this listing. Please view the pictures of this item, because what you see is exactly what you will be receiving! Please see my other postings for more firearm parts, including No reserve auctions with free shipping starting at $0.01! Free shipping! Please see my other listings for more firearm parts. I do combine shipping on multiple items.