Learned the hard way with Chain Pickerel; lucky to get then to shore before they sliced the leader.
I have used Haywire from Orvis. Umpqua also makes them. List for $15 for six.
I use the 4 inch / 38 lb. Almost as easy to use as a snap swivel in spinning. I also have found that they do not affect my cast (as bad as it is). Great for quick change of fly. If the eyes are not as good as they once were and you have fumble fingers, especially with wet hands, they are handy.
They are subject to bending, but can be straightened.
Considering I don't know what will take my fly on a given day, Pickerel, Pike, Bass or Pan-fish, I leave the haywire on nearly all the time.