Our manhole includes base, risers, top, steps, o-rings, pipe to manhole connectors as specified, and precast flow channel. Our stock tops are 2 ft and 3 ft eccentric or concentric cones with 24" clear opening or a flat top slab with 24" or 36" clear opening. Custom tops are available. Doghouse holes can be formed when it is necessary to drop the manhole over existing pipe. An extended base is also available.