I have long coveted the special flare nut wrenches they offer -- they have a little hinged part which connects the two sides of the main wrench so as to form a box wrench when it is closed, preventing the flexing which often causes flare wrenches to slip just like open enders on the really stubbornly rusted fittings. Does anyone have any first hand experience with these?

I'm just an amateur (at present, anyway), but I need to use my flare wrenches several times a year, not just several times a lifetime. Maybe it's because I've got five kids between 22 and 34, along with a son-in-law and some soon-to-be daughters-in-law who expect me to heal everything from a '66 Mustang to a 2002 Audi AllRoad.

My other car is a '91 Ford F-150, a '95 SAAB 9000, a '90 SAAB 900, etc., etc., etc.