The Merrow MG-3U is a 3-thread industrial sewing machine that is meant for putting a decorative edge on emblems and patches. It makes a 1/8" to 3/16" stitch at a standard rate of 28 SPI (though this can be decreased or increased to 20 or 40 SPI respectively), yet even while running at 5500 RPM still operates under 90 dbA. The MG-3U carries a 10 year warranty, though it is expected to run for years after that with routine care.

Since 1838 Merrow has manufactured the world's best overlock sewing machines. A Merrow Machine is built to sew a more precise stitch and operate longer than any other competitive sewing machine in its class. Merrow Machines are engineered and manufactured more carefully, designed to last decades, and supported with a network of 156 agents in 65 countries. The Merrow Sewing Machine is The Most PRECISE and TOUGHEST sewing machine manufactured in the world

Overlock stitching was invented by the Merrow Machine Company in 1881. Merrow's original three-thread overedge sewing machine is the forerunner of contemporary overlocking machines. Over time, the Merrow Machine Company pioneered the design of new machines to create a variety of overlock stitches, such as two, and four-thread sergers, the one-thread butted seam, and the cutterless emblem edger. Today Two- and three-thread formations are also known as "merrowing".