WC Pan connectors with basin waste connection ?

Hello all,
I'd like to install a toilet with a pan connector that has an option to accept the wastepipe from a washbasin such as this product: McAlpine WC-CON1V, described as "Straight 90 - 118mm Pan Spigot to 110mm Pipe with 1¼ inch Universal Pipe Boss"
http://www.mcalpineplumbing.com/productlist.asp
BUT, I'd need the flexible version: McAlpine WC-F23RV
described as "150mm > 340mm Flexible Connector with Vent Boss".
My question is: do both products serve the same need or as the different descriptions suggest, does the flexible one just have a vent and not a pipe connection ? (They look the same)
McAlpine don't take questions from the public.
Thanks for your time.