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Featured here is a Proto Torque wrench of the dial type. There are a variety of styles of torque wrenches. The cheapest and least accurate are the 'bent beam' style. They are really a breaker bar with a measurement of how much the handle bends when you pull on it. Another style is the 'clicker' kind, that has a handle that slightly breaks away when you reach the preset torque and 'clicks' when it does, and the third major type is the dial type, that actually has a dial and a needle that points to a numeric scale.
This particular one is one of the largest you will see, capable of torque setting up to 2000 foot lbs. although only 4 sections of handle are assembled here as I only needed 1000 lbs of torque for this job the unit comes with 5 sections of handle totalling about 9 feet in length.
The 'bubble' on top holds a penlite battery and if you preset the torque you want, the light is suppose to come one when you have arrived so you don't have to read the dial you can't see from 8 feet away. Practically speaking, using the wrench is a two man job. One monkey to pull the handle and another to read the dial and move the wrench as it is so clumsy as to be not easily managed by one person.
The alternative to a wrench like this for high torque settings is to use a torque multiplier. They are typically a planetary drive and will allow you to use a smaller torque wrench multiplied by the ratio of the multiplier. For example if I had used a 4:1 torque multiplier, I could have used a torque wrench with a capacity of 250 lbs to achieve the 1000 foot lb setting.