Review on ThreeBulls 30 Pcs Silicone USB Cap Port Cover: Female End Black - Anti Dust Protector with Superior Quality by Ron Patel

Good product for the price that does what it sells for will, with USB ports -A and the opening closed.I don't know about "waterproof" for this item, but I wouldn't trust it by submerging a product with this item in water and expecting the lid to be waterproof I bought this item to keep dust out and it really is very good Yes this seal strength does not hold water however do not push it too far If you do this it will be very difficult to take out This one small protrusion on the top of the product helps a little, but don't rely on it too much or it will break.You'd better only insert the product 50-80% into the USB port so that it protrudes a little and do it easy to remove Works like a charm for me.