The part you are asking about is part of the Rolux venting system for Rinnai condensing water heaters. I do not have all the information you requested, but will answer to the best of my ability: The inner pipe is 80mm, the outer 125mm. You will likely need a 5.5"-6" hole for your penetration. The unit includes 3 elbows, a 14.2" vent extension, a 19.5" vent extension, and a telescoping vent extension (2.2"-12"). The housing is also adjustable in height. Used with in the application described above, no clearance to combustibles is required.