The leather sheath that came with my F1 didn't even have a plastic liner. This zytel sheath is well made and a good fit except that the transport lever allows the knife to come out too easily when it should lock it in. I still give it good marks because it is easily fixable by adding some small plastic material to the lock mechanism where the lever presses on it, making it push further into the sheath against the knife handle. I carry side draw with the knife under my armpit so it doesn't take 20 minutes to get it out from under clothing/coats, and this sheath is perfect for that. I am off to find a tiny piece of plastic and some glue.