Filter basket flange SERA BioActive 250 UV, SERA BioActive 400 UV, and SERA Xtreme, suitable for external filters. The flange is branded, molded, and easy to replace, made from high-quality materials. It is non-genuine, new, and unused. To extend its lifespan, it is recommended to lubricate with special silicone grease every second or third time you open the filter.