Retailers such as Baby Lock, Brother and Singer offer sewing machines with serger stitch and coverstitch functionality. The models from each manufacturer differ in capacity, capability and price but generally feature four or more thread spools, one or more needles, variable speed control and machine lighting.
As of 2015, the Baby Lock brand sells nine varieties of sewing machines that feature serger stitch and coverstitch capabilities. The Ovation and Evolution models each accommodate up to eight thread spools, multiple needles, and loopers instead of bobbins for returning the thread to continue the stitch. The Baby Lock Diana has a five-thread capacity that separates it from the remaining six models.
Brother International offers seven models of serger and coverstitch sewing machines. These units each feature two needles, loopers, and capacity for two, three or four thread streams, depending on the specific model. Similarly, Singer sells five models of four-thread sergers as well as the Professional 5, a high-end five-thread machine.
A serger stitch, also known as an overlock stitch, uses one to four threads, one or two needles, and one or two loopers. Additional threads for a single stitch strengthen the output stitch. The process of creating an overlock stitch on a machine takes six steps.