"Woollie-like" nylon is a common fiber type for serger threads. It is fluffy and has good stretch, but is not heat resistant, can fade over time, and can turn brittle. Textured Polyester is a polyester version of a "woollie-like" nylon serger thread. Great stretch, coverage, and a higher heat-resistance, Polyarn and ProLock are great threads to use in your loopers when serging.
Tex 26 Texturized Polyester thread. Created specifically for Serger and Overlock machines. Polyarn is a premium “woollie-like” texturized polyester thread. Polyarn has excellent elasticity, recovery, and flexibility, which makes Polyarn the top choice for garment construction with sergers and overlock machines. Because Polyarn is 100% polyester, it has a higher heat resistance than woollie nylon threads. These beautiful colors are colorfast and can be commercially laundered without risk of fading. With its excellent coverage, Polyarn can be used for simple hems or fancy stitching.
Tex 35 Texturized Polyester thread. Created specifically for Serger and Overlock machines. ProLock is a new texturized polyester thread (DTY) designed for serging on fleece, knits, and stretch fabrics. Available in 60 colors, ProLock is colorfast and can be commercially laundered without risk of fading. With the bulk, elasticity, and flexibility popularized by “woollie-like” nylon threads, ProLock has all these traits plus the addition of higher heat-resistance.