A SUS303 stainless adapter converting an AN3 line to an M10x1.25 metric thread. This pitch shows up on a good number of Japanese brake and clutch components and is the one most often mistaken for M10x1.0, so a thread gauge is worth five minutes before ordering — the wrong pitch will engage a turn or two and then ruin the port. Used correctly, it lets a standard AN3 braided line serve a metric-threaded calliper or cylinder with no modification to the vehicle and no stacked adapters. SUS303 stainless gives good corrosion resistance where brake fluid, water and road grime collect. After fitting, bleed the system thoroughly and hold firm pedal pressure while inspecting the joint for any sign of weeping before the car is driven.