Cometic makes a great one. It's called an AFM gasket and can be ordered directly from Cometic, 1-800-752-9850, ask for Jason Moses in Sales and Marketing. The gasket has an aluminum core with expanded nitrile rubber bonded to it (all over). Cost about $18. I've had one on for 4 months and not a drop or seep or weep. Most time they can also be re-used.
Retired Navy, MCPO