adding gate valve to sewer line

[tbart16]

could someone please shoot me a website where I can buy a 3" ABS knife style gate valve I can only seem to find pvc ones I am just not comfortable mixing ABS and PVC and the white valve on the black pipe would drive me nuts thanks

 

[Ned]

Any RV supply store will have the Valterra valves.

 

[tbart16]

only thing I have been finding are the repair kits. I would actually like a complete valve 3" slip x slip

 

[Gary RV_Wizard]

Is this what you are calling the kit?

http://www.pplmotorhomes.com/parts/rv-toilets-tanks/20097.htm

And you are looking for a black ABS, 3x3 slip coupled valve instead? If so, here is one source:
http://www.pondparts.com/prod251.html