With the purchase of your Vandy Vape RDA you will receive three different 810 style drip tips. All 3 drip tips are made out of different materials that include Resin, Ultem, and Delrin. The Ultem and Delrin drip tip have the same exact dimensions, they are just made out of different materials. Both drip tips have an 18mm bore and raised rings going around the circumference to provide some light texture. The Resin drip tip is a little taller smoother, and thicker, it has a 17.5mm bore. If that is not enough to suit your needs, we also include a 510 drip tip adapter so you can run your own standard 510 drip tips on the Lit RDA. At Vandy Vape, we are all about giving our customers choices.The Lit RDA features a two-piece top cap and sleeve. The top cap has one o’ring that holds it securely in place with a beautiful tolerance to it. There are two different types of airflow slots. Both of them are the shape of a rhombus. The first airflow slot is a series of 16 holes in the shape of a rhombus. Each hole measures 1mm. The second air flow slot is a series of diagonal cuts, also in the shape of a rhombus. The 7 diagonal cuts measure 1mm, 2.5mm, 4.5mm, and 6mm respectively. The holes will give you a smoother vape while the diagonal cuts will give you a much airier vape. The interior of the top cap has a beautiful conical design that is conducive to the superior flavor the Lit RDA has. There is also some knurling on the outside exterior of the top cap so you can get a good grip in order to adjust your air flow.