Dukal Corporation Dukal X-Ray Detectable Gauze Sponges. USP Type VII gauze, 100% woven-cotton with blue filament that runs through each sponge and has a unique wave pattern to ensure easy x-ray detection. Sterile sponges are packaged in rigid plastic tray with peel back lid. Both sterile and non-sterile sponges are banded in 10’s to ensure accurate count.