Maxi Lock Swirls Blueberry Cobbler Serger Thread 53-M55 Maxi Lock Swirls Blueberry Cobbler Serger Thread . Decorative 100% Spun Polyester. Great variegated colors, excellent seam strength, consisten sewabiltiy, mildew and UV light tolerant, shrink and abrasion resistant. Thread is ideal for decorative serging applications. 18 colors to choose from. 3000 yd cone. 53-M55