This is a new 16" Knappco manhole. I used to manufacture asphalt sealcoat machines and this new manhole thats been setting around the shop for a few years. We used this model of manhole on all of our sealcoat tanks from round 200 gal. to 1000 gal. as well as some special order square tanks.  It has some minor surface rust from humitdy in my storage room but other than that it's new and in perfect condition.  It is 16" in diameter and the weld ring is 6" tall.  It is made of heavy gauge steel. It has a rubber seal under the hinged lid that seals tight with no leakage when transporting liquid. It has a cam type lever that pressures the lid tightly closed.  It has a spot for a padlock for locking the lid closed keeping kids or foes from contaminating your sealer. The weld ring is thick enough that you won't get any warpage when welding it to your tank. If your just getting in to the sealcoat buisness or adding extra sealer storage to your buisness, building your own tank with hand crank operated agitator is very reasonable and easy to do. All you need is a clean tank (preferably new), a couple of sealed 4 bolt flange bearings from a commercial supply store like Grangers, some rubber to make gaskets for mounting the bearings to each end of the tank, a round cold roll shaft, some steel for your paddles and hand crank, misc.nuts and bolts,  access to a welder and misc. hand tools, and some ingenuity.  This is a top of the line manhole that really tops off the job in efficiency and appearance. Thanks for checking out our sale.