The face of a Precision Brush Company Open wound coil brush is measured from the left edge of the first loop to the right edge of the last loop. When you receive our brushes it is important to measure them after they have been mounted on the shaft. The face length of Open wound brushes tend to shrink during shipping. Depending on the filaments used and the dimensions of the brush, the filament will often flair out past the edges of the metal channel. If there are critical dimensions regarding your required brush face please let us know when working with our engineers or filling out our design a brush form.