When you want to make the most of your serging time, with professional results, the MyLock 634D is unmatched. It has 2 needles and 2, 3 or 4 thread overlock stitching. Threading is a breeze due to color-coded thread guides and an easy lower looper threading system. The MyLock 634D also lets you quickly switch to rolled hemming without changing the needle plate. 2, 3, or 4 thread serger, Lay-in thread tension dial, Threading chart, Color coded thread guides Tension release device, Easily accessible lower looper guides, Changeable thread guide, Quick change rolled hem Lower looper pretension setting slider, Easily retractable upper knife, Adjustable foot pressure, Snap on presser feet Adjustable stitch length 1mm to 5mm, Differential feed ratio 0.5 to 2.25, Adjustable cutting width 3.1mm to 7.3mm, Maximum speed 1,300 spm Bonus Kit Includes: Beading Attachment, Blind Stitch Foot, 1/8 Piping Foot, 3 Pack Needles Serger Size 14