The O'Neill Siren vest is designed with a lightweight FluidFoam neoprene shell for minimal bulk and ultimate comfort. Segmented foam core, strategic armhole size, and anatomical flex points increase mobility. Integrated lumbar support pad eliminates stress on your back. Other features include concealed dual belt system with quick-release buckles and durable, overlock stitching for super strong seams and long-lasting use. USCG approved. Sizes: 4(30"-32"), 6(32"-34"), 8(34"-36"), 10(36"-38"), 12(38"-40"). Integrated lumbar support system USCG approved | Women's Siren Competition Life Jacket - Black/Turquoise - 10