100% polyester Do these insoles need to be cut to size? Yes, these are trim-to-fit. Superfeet insoles are made to be trimmed to fit your shoes and boots; follow cutting instructions before use, and if you're between sizes, size up and trim down to fit Do these use memory foam? Pressure-sensitive memory foam molds to the shape of your foot for personalized comfort; fits roomy to moderate-fitting footwear How does the arch support work? No casting or baking required; insoles help stabilize the foot, reducing stress on feet, ankles, knees, and back Do these help control odor and moisture? Moisturewick top cover helps reduce odors and keeps feet fresh; gentle, low profile arch support helps stabilize the foot Is this the same product I used to buy? Yes — formerly sold as Superfeet COPPER, this is the same trusted insole you know and love, now with a new name. All-Purpose Memory Foam Support (Copper) insoles are the same great arch support insoles you love, now with a new name