SLR4D is a 3, 4 thread overlocking with differential feed overlocker and features;
  -  Adjust the ratio, by turning the dial.
  -  The adjustable differential feed helps produce quality seams, gathers and frills. 
  -   Bite width ensure correct width of the stitching to suit the fabric type. 
  -  Built in stitch length adjuster allows wide variation of stitch length.

Please use a Roll hem Needle plate B & a B-foot for roll hem.