Ridge Tool Company , the most well-known manufacturer of these tools says that (unlike an adjustable wrench) there should be a small gap behind the pipe and the front of the adjustable hook jaw.

Plumbers' wrenches look like spanners, but they have extra-long jaws good for gripping pipe fittings. Adjustable wrenches - ...

An adjustable wrench saves you space and money ... the broad edge instead of the movable one to protect your wrench. A pipe wrench is one of those tools that can’t pull double duty, but when ...

Need an adjustable wrench for tightening nuts ... the wrench that can sink its literal teeth into pipes. That’s a pipe wrench ...