https://www.stortz.com/product-category/roofing-tools/sheet-metal-roofing-tools/standing-seam/double-seamers/
Roofing Seaming Anvils - Stortz & Son Inc.
Seaming anvils are used as back stops to form metal over. They work well when you are hand locking standing seams.
seaming anvilsroofingstortzsoninc