The Osmo Action Filters (Professional) are made from German Schott glass and have undergone multiple grinding and polishing processes. A nanometer-sized, double-sided, and multi-layer vacuum coating provides waterproof, oil-proof, dust-proof, and scratch-resistant protection. Attach the filter directly to the device to maintain water and dust resistance. The frame, made from aerospace aluminum, features a knurled pattern for quick attachment. The inner part of the frame is covered with silicone gel to protect the original filter from scratches during attachment.