I have not worked with this wrench, but I opined based on its thin structure, especially the lower threaded rod that can not tolerate a high pressure.
Based on a visual investigation; the monkey wrench seems so much resistant and powered than this one.
Of course I don’t know, whether this wrench is called monkey wrench or not, but it seems very strong and resistant
from my example posted further above, you always put the pressure on the thick side of the wrench and rotate in this direction, there is not much pressure on the other side other than holding the wrench together. rotating in the other direction will not work well and is not meant to be handled that way, the jaws and the entire structure, mechanics are built to be handled one way, thats why i am saying it may look deceiving
your wrench looks like its for a complete different user case, you would not be able to mount or demount any large pipes if any at all, flat jaws are just not right for that. it looks more like for mounting cast iron fittings and taps, or anything which has flattish sides. for bolts and nuts it might work too but that might not be so good for the nuts.
I understood. So the position of the t-rex wrench should be changed up to down, and down to up for opening or closing a pipe, as the pressure is imposed on the upper handle in the picture.
However, I didn’t deny the t-rex advantages. If it was not a useable wrench for some tasks, it would never manufactured. I only was doubtful about its resistant compared with the monkey wrench. So you believe, it is not weaker than other pipe wrenches.
Okay 
i had to reread again 
are you actually referring to the apprentice?
That would be disrespectful. 
oh come on, i can remember we also had some handles, apprentice years were tough times 
being a monkey would be far from an insult then 
…And in Denmark the crescent wrench is referred to as a “svensknøgle” - Swedish key/wrench. Probably because most of our crescent wrenches are from the Swedish company Bahco, who made a 100 million of them… After some inventions and patents by the Swede Johan Petter Johansson around 1892. Johan Petter Johansson - Wikipedia
