This aluminum adapter has 12x1.5mm male threads on one end and an 10AN male (7/8-14 thread, 37° flare) on the other. This adapter fits the outlet side of the popular Bosch "044" (FP200) fuel pump or the newer Bosch FP200-7 Fuel Pump. Anodizing color may vary from photo.
The metric end is hollow, without a sealing surface. You must use a 12mm Aluminum Crush Washer (Part No. 3278-M12, sold separately) with this fitting.