It is made entirely of 316L stainless steel, the insulators are made of PEEK and the Pins are 24K gold-plated. The liquid capacity configured in the boros with the 326 RBA installed is over 5ml. The inner bell can be rotated via a 3.5mm Allen key from the outside. It accepts a single coil, the air comes directly under it and the hole can be adjusted with the 5 different pins included in the package. The flow of liquid is through 3 holes of 0.8mm per side..