Why isn't the pipe included?

1 5/8" or 1 7/8" diameter dock pipe is purchased separately which allows you to size lengths according to your specific needs.  In addition, dock pipe in long lengths is very difficult and subsequently very costly to ship especially in smaller quanitities.  Ultimately it can be purchased locally (lumber yard or plumbing supply) at a much lower cost.

What options are there for width and sizes?

Axel is 1 5/8" or 1 7/8" diameter dock pipe that is purchased separately which allows you to size length according to your specific needs.