1" Brake Master Cylinder. This product is of high quality and ideal for you Chopper! It already has a reservoir and comes with the lever and fits on a 25.4MM bar.

Material : Aluminum alloy
Color: Black
Size: Fits 1" / 25mm Handlebars
Mirror thread: 10mm / 0.39"
Bore size: 14mm / 0.55"
Banjo Bolt Size: M10

WITH Brake Light Sensor/Switch