Leggendo la descrizione, la firma dell’inventore mi pare inequivocabile….
“The patent describes use of an “air permeable absorbent” material (green, in all figures) sitting just underneath the dual-lipped wiper seal that would prevent any lubrication oil inside the lower legs from escaping. This sounds much like a generic foam ring that would be found inside any modern suspension fork. The document says this component could be made of closed-cell foam, open-cell foam, or a sponge material formed from polymer-based materials.
Se si parla di spugnette (o pugnette) uno solo può essere!
Da parte mia dico che: intagli, fessure o scavetti sulla superficie dello stelo preferirei non averne.