This is the part which is mounted at the base of the roof to collect rain water from the roof to lead it away from the house in a controlled manner through a downpipe.
The gutter angle is mostly used on hipped roofs or porches where you want to lead the water round a corner to another gutter.
The gutter joint is used to get a waterproof joint between gutters or between a gutter and a gutter angle.
You mount the gutter end at the end of the gutter in order to stop the water and to get a good looking finish of your gutter.
The gutter outlet is the part that connects the gutter with the downpipe.