its the spider of the woofer only. some dont need any, others especially coated spiders which are sometimes on pro drivers are very stiff when new, you can feel the difference with fingers on the suspension from a new and used unit. if its audible depends.
there are lots of similarly priced passive speakers that dont even compare, all many talk about is like “new super tech diamond coated nano-tech tweeter” and other nonsense that dont matter. b&w, focal etc have made no real improvement in speakers for decades. its the same ancient passive design with the same acoustic design. beolab 90 is an all-in effort.