Peterson System Standard model 31:

This is my go-to pipe for a quick smoke if I only have 10 or 15 minutes. Of course, one should never rush a pipe smoking experience, but some mornings are more hurried than others.

This was my first Peterson System pipe (I wrote about my other one previously). Of all the system pipes offered this is the only one that is straight. The bowl is pretty small and only about half the depth visible from the exterior because, like all System pipes, there is a reservoir below the bowl for the fluids to accumulate, but, because of the shape, unlike the bent pipes, there is no way to drill another hole at an angle that a curved bowl would provide.

Here's a cross-section of how a "normal" Peterson System pipe looks: