Subheading 711510 covers platinum (and platinum-alloy) catalysts woven or knitted into a mesh or gauze form, as used in ammonia oxidation and nitric acid production. Pellets, sponge, or other non-woven catalyst forms would not meet this description and would fall instead under 711590 or potentially another heading depending on their form and function.

Heading 7110 covers platinum in primary or intermediate forms (unwrought, powder, semimanufactured strip or wire), while 7115 covers finished articles made from precious metal. A platinum wire that has been woven into a catalyst gauze is a finished article and belongs in 7115; the same wire on a spool, not yet fabricated, would remain in 7110. The degree of further working and the article's end-use form determine which heading applies.