This 20mm quartz enail banger works perfectly with a 20mm round coil. This design keeps the coil rested against the quartz to maintain the right temp at all times. It also features a deep bucket-style dish with a large surface area, perfect for providing space for cool air to mix with the vapor and acts as a natural splashguard. This in turn keeps the concentrate from being wasted. A small handle on the left side of the nail, level with the bottom of the dish, provides a resting place for the coil, which wraps snugly around the bottom half of the dish.