I just had to replace the ABS toilet flange in our front bathroom. I was very happy to find that there was a rubber slip fitting where the 3 inch ABS pipe enters the top of the black tank. Made my job much, much easier. Hope this helps.
Brad, Sandy, Amber (shephard), Niko (shiba inu RIP little buddy)
'12 F-150 XLT SuperCrew 4x4 Ecoboost with MaxTow
'12 Flagstaff V-Lite 30WRKSS