Steel Metric Flareless Fitting, 8.00 mm L Series To G 1/4 MaleBSPP With Seal

That's what it handles. One end accepts the 8mm metric tube using an L Series flareless connection, and the other end threads directly into a G 1/4 male BSPP port. It also comes with an integral seal already built in, so you're not hunting down a separate bonded seal or backup washer to get a leak-free connection at the port end.