Biologix Drosophila Fiber Vial Closures by Biologix are autoclavable fiber plugs that seal fly vials while staying breathable and keeping mites out, with minimal shedding and reduced evaporation. Choose 24 × 27 mm closures for narrow plastic vials, 23 × 27 mm for narrow glass vials or 27 × 30 mm for wide vials. Packed 100 per bag, 1000 closures per case.