Based on this product's specifications, here are some alternatives and similar models
Exhaust/Post Filter for Dyson DC77 vacuum — JETtools SB11038 (replacement for 966977-01)
Summary description:
JETtools SB11038 is an exhaust/post filter designed as a replacement for Dyson DC77 series vacuums (compatible with part 966977-01). The filter captures fine particles from the vacuum’s airflow before discharge, helping maintain suction performance and reduce re-emission of dust. Intended for routine replacement to preserve filtration efficiency and appliance longevity.