Replicating the original bass drum hole reinforcement, these have a snap on design.The O’s allow for minimal head removal with more variety in tunable ventilation as well as external microphone access. Features 4″RoundWhite finishProtects your port from rips, snags, and tearsAdhesive rings used to hold the Bass Drum O’s in placeAlcohol swab included for a clean, permanent application Reviews There are no reviews yet. Be the first to review “Bass Drum O’s 4″ White Bass Drum Port Rings” Cancel replyYour email address will not be published. Required fields are marked *Your rating * Rate… Perfect Good Average Not that bad Very poor Your review *Name * Email * Save my name, email, and website in this browser for the next time I comment.