The Sig Sauer P320 TXG Grip Module uses tungsten-infused polymer that is then molded into the part. This patent-pending process results in a grip module that has the weight of steel and the flex of polymer. Install your P320 Fire Control Unit into the TXG” and you’ll have one of the flattest” softest shooting pistols on the range. Requires complete P320 Fire Control Unit and X5 or Full-size slide assembly. Grip module weighs 13.3 oz. This model does not come with the internal weight or magazine well.