The hop spider is stainless steel mesh hop filter that hangs from the the edge of your kettle. Up to 12 oz of hops are poured directly into the spider during the boil. Made from 304 stainless steel. The basket is 13.75 in (35cm) high with the opening at the top being 5.9 in (15cm) diameter and tapers down to a 3.9 in (10cm) diameter at the bottom. 0.4 mm aperture mesh.