Sunbrella Loom Four Castlerock 43503-0001 Retweed Collection Upholstery Fabric. The RETWEED collection is a sustainable line of performance fabrics from Sunbrella containing up to 93% recycled content. The textural look of hand-loomed textiles ensures no two rolls are alike. The textures of these weaves offer familiarity, a soft touch, and warmth to living spaces. Note that there might be dye lot differences due to the recycling process.