From Floplast
This 92.5 degree branch is one of the integral parts of any soil pipe system. It is used to bring horizontal and vertical pipe runs together, usually when connecting a pipe from a WC into the main vertical soil stack. The 92.5 degree angle creates a fall that is self-cleansing. The top two connections are ring seal sockets, the bottom of the branch is a spigot that can be fitted into another ring seal socket.