The 18-G by Merrow is similar to the 18-E in that it produces a standard 1/2" single-thread blanket stitch except that it can lay an elastic in the stitch.
The Merrow MG-3DNR-1 is Merrow's three thread Purl Stitch overlock machine, designed for medium weight stitches is used for decorating, cleaning, and sealing the edge of fabrics during production.