A naked portafilter handle has no base to the bowl in the handle. A basket (usually between 18 to 21g) hangs in the handle and the perforated bottom is therefore exposed and visible. It is advantageous as it confirms that the distribution of coffee is uniform and even. If this is achieved you should see no spraying of coffee and the extraction will funnel centrally to form a single pour. It is often said that the extraction is smoother than when using a standard portafilter handle.