The MyLock 644D includes essential features for simple serging. The differential feed system of two feed dogs virtually eliminates puckered edges on woven fabrics and stretched edges on knits. Its unique rolled hem conversion feature eliminates the need to change the needle plate, foot, or tension setting for rolled hemming. Janome has restructured the lower looper guides for easy threading. Color-coded guides are easy to follow for 2, 3, or 4 thread serging. All of the features on this machine are specially designed to make this serger one of the easiest to use on the market today.