The 'red sized' terminal crimptool is used to crimp terminals in the gauge 22-16 range.
It is also used to crimp non-moistureproof endcaps and non-moistureproof splices.
We use the AMP 47386-4.
Here's a gauge 20 wire that we are going to crimp into a red terminal.

The terminal is put in the crimping head of the tool.

The wire can now be inserted into the terminal.

Make sure that the rear of the terminal firmly grips the insulation for strain relief.

picture by: http://aeroelectric.com/

Now that we have made the crimp onto the terminal we can inspect it.

The terminal.

The crimptool can be set to three different tightness settings. 1 being the tightest.
Looking at the strands of wire we can tell wether the tool should be set tighter or looser.

The tightness can be set by moving the pegs to holes 1, 2 or 3.

When crimping terminals, splices or endacps with this tool, Here are some more guidelines.

Some non-moistureproof splices.

Some endcaps, the red non-moistureproof endcap is crimped with the red terminal crimptool, the blue one with the blue terminal crimptool and the hat shaped one with the endsplice tool.