Wrong size for many masks/filters out there, nor do these lock into place.
Website states:<br />【Size】Outer Size: 40mm x 35mm/1.57" x 1.38" (Approx.); Inner Diameter: 18mm/0.71" (Approx.)<br />This product measures 26.6mm on the fitting diameter, meaning it won't fit ANY of the 3 masks we own.<br />We're trying to get a refund but be aware that these won't be compatible with the base camp and other masks available on Amazon. not to mention with flimsy construction and inability to properly lock into place it's definitely a lose-lose situation.  If the holes on your mask aren't 27mm I would NOT recommend this product.
Rating: 1 stars