There is a brass part by turn-milling compound machining, side round holes and the central slot are one-off processing, which make sure the concentricity and tolerance. Besides, this part is made of quality brass with nickel plating, so you can see 2 colors. turn-milling compound machining is very suitable for complex round part or lateral porous/slots, like shaft or filter. welcome to inquire if you have similar part to produce.