1/4" fastener for the Walter handgrip.
Remember yu have the option of ordering this 3D-printed one, but we recommend getting a metal one.
There are various tripod-type fasteners available at small cost from eBay, Amazon, and many other online retailers.
Black D-ring from eBay
Plain screw from eBay
D-ring from Amazon UK
Plain ring from Amazon UK
Or if you venture in finding your own option, please use this guide