The relationship between yarn or sliver count and felting-tube size is discussed and general recommendations for tube selection are made. Effects on yarn bulk and stability are described. Material feed to Periloc via the input creel and friction feed roller is discussed, and the felting of more than one end per tube as a means of increasing productivity and/or producing set yarns is described. The role of pressure release holes in the felting tube is explained, and a recent development designed to increase tube wear life is described.