ProMag Sling Swivel Stud for Picatinny Rail Adapter with Palm Rest, Black Unique design allows the adapter to fit a large variety of rifle fore ends Adapter keeps the feet of the bipod from damaging delicate stock finish 4  long mounting rail is precision machined and type III had anodized to meet MIL-STD 1913 rail specifications Provides steel on steel attachment to the sling swivel stud No permanent modification is required