The WDT tool is machined from aluminum and anodized. Inside is a Delrin insert which allows you to install up to 17 needles. Though I recommend using up to 9 at a time. Magnets are installed at the end of the tool as standard. With this insert, you will also be able to mix and match different diameter needles. I have always been a fan of thin needles where other WDT tools on the market use thick 0.4mm needles. From my experience, larger diameter needles move the coffee around rather than fluffing and breaking clumps. The larger needles will create more clumps, opposite of what a WDT tool is meant to do. Non-black colors are produced in small quantities.
Each tool comes with one pack of 0.22mm and one pack of 0.25mm needles. Each pack contains 10 needles. Needles are custom made with a rounded end which won't stab you. #notacupunctureneedles
Note: Avoid using the ceramic coated options to pick up the magnetic puck disc screens