Unused item. My family accidentally ordered it. It says: Filter for Ergorapido vacuum cleaner zb3125bl zb3301 zb3111ak It seems to be compatible with EF150. It should work with the ZB31/33/34/35 series, but I'm not sure if all models in the same series use the same filter. If you're concerned, please let me know your vacuum cleaner model number, and I can check for you. (For example, even if it works with zb3111ak, it seems that ZB3101 and ZB3102 use different filters, so I can't definitively say "31 series".) [According to AI research] Regarding compatible models, filters for the "ZB33 series" such as ZB3301 and ZB3311 are sold together as EF150 (or compatible) under the manufacturer's part number, and are compatible with multiple models such as ZB3301/ZB3302AK/ZB3311/ZB3320P/ZB3327G/ZB3324B. On Rakuten and Yahoo! Shopping, compatible filters are sold with descriptions like "ZB33/34/35 series compatible" or "ZB33-FF compatible," listing ZB3301, ZB3311, ZB3323B, ZB3324BD, etc. as compatible models. https://shop.electrolux.co.uk/vacuum-cleaners/cordless-vacuum-cleaners/filters/c/175 It will be sent by regular mail in simple packaging. Please understand.