The versatile vertical tube overlock sewing machine has powerful functions such as vertical seam, reverse seam, rolling collar seam, and folding seam. The adjustment of stitch density requires pressing a button to achieve stepless adjustment. Simply operate the external adjustment lever to adjust the differential ratio. One machine can excellently fulfill the sewing requirements from thin to thick materials and various processes. It not only gives you the flexibility you need for multiple varieties, but also includes various functions that reflect the high quality of the product in all aspects.