This Sony NP-FW50 dummy battery to P-tap cable was designed to be used with (although not exclusively) the Tilta Universal Battery Plate. It allows you to power cameras that use Sony NP-FW50 batteries (such as the Sony a6 and a7) as well as Sony NP-FW50 power-based accessories through a P-tap power port.
So far so good. One shoot day in the can. No issues. I’ve been through a few of these from other companies. One the camera refused to recognize, one that fried out my A7Sii motherboard. Happy to find that Tilta’s works.