Self-Adhesive Lid Filters 18mm | 50 pieces

The Self-Adhesive Lid Filter is a small synthetic filter patch with an adhesive backing. Stick it onto a drilled hole in a jar lid (or onto a grow bag) and your culture can breathe through 0.22 micron filtration — fine enough to block mold spores and bacteria, but permeable enough for healthy CO₂/O₂ exchange (FAE).

These filter patches are the easiest way to convert any plastic or metal lid into a breathable, contamination-resistant jar lid. They are typically used together with self-healing injection ports: the filter handles air exchange, the port handles inoculation.

How to use

1. Drill a clean 7.1 mm hole in your jar lid using our 7.1mm Cobalt Steel Drill Bit . The 18 mm sticker easily covers a 7.1 mm hole and seals around it.
2. Deburr the hole edge — run your finger, a utility knife or a folded paper towel around the rim to remove any plastic or metal burrs. A smooth edge is critical for a clean adhesive seal.
3. Wipe the area around the hole clean with 70% isopropyl alcohol and let it air-dry completely.
4. Peel the backing off the filter patch and press firmly over the hole, ensuring full 360° contact around the edges. Hold for 10–30 seconds.
5. The lid is now ready for sterilisation in a pressure cooker or autoclave. The adhesive survives 121°C pressure-cooking cycles.

Specifications

• Diameter: 18 mm
• Filtration: 0.22 micron synthetic media (polypropylene)
• Recommended hole size: 7.1 mm (compatible with our drill bit)
• Adhesive: industrial-grade, autoclavable
• Hydrophobic — water will not soak through
• Pack contents: 50 filter patches

Typical applications

• Grain spawn jars (especially PP plastic lids)
• Liquid culture jars
• Agar work in small vessels
• DIY breathable lids