The ZZ 3100 sewing unit using a is a high quality twin needle chainstitch sewing head designed to automate attachment of zippers to trouser flies by using endless zippers from the roll. This sewing unit provides numerous advantages such as elimination of fusing operation of fly piece and a consistent seam width due to the special edge guide system. The accurate transport technology with separate material feed for the zipper and fly piece guarantees a puckering-free operation even on difficult to feed fabrics. On the other hand , the use of continuous zipper leads to minimum zipper waste. The ZZ 3110 version is the same machine with the additional photocell controlled length adjustable Scissors Unit.