This one is unique --
Line gauges/wrenches that come in different diameters and can be wrapped around a fuel line fitting or plug to loosen it -- the same can be done with open end line wrenches, but these are for OEM applications.
Not a very clear explanation i know -- so here are a few pics. Assume the 1/2" nut is a 1/2" line fitting so the 1/2 gauge is selected and "wrapped" around the line in order to loosen and tighten the fitting. It provides a VERY tigh fit and because of the innovative design, this tool will NOT strip a fitting.
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0187.jpg)
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0188.jpg)
Gauge/Wrench is "wrapped" around the fitting --
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0190.jpg)
3/8" socket wrench is attached --
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0189.jpg)
I found a slew of these carburetor adjustment tools and belt tension gauges in my old tool stash -- quite a treasure trove of tools that used to cost a fortune but now seem all but worthless to most folks. I tried to explain their use to a friend of mine, but I sold my last Holley 4165 years ago, and without an appropriate carburetor to explain the procedure I might just as well have talked to a wall.
It seems that carburetor know-how has faded into history, and many younger folks have absolutley no clue how they work and how they can be adjusted and modified.
All the tools came in a nice kit (mostly Holley, GM, Rochester specific).
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0080Medium.jpg)
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0081Medium.jpg)
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0082Medium.jpg)
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/PICT0083Medium.jpg)
Very interesting! I can't say I've seen that style line wrench before.