Abstract: A service tee comprises a tubular T-piece 1 having a through-portion 2 with a flexible lower end 6 for connection to a gas or water main 70 by way of a hole in the wall of the main and a side branch portion 3 for connection to a service pipe. The end 6 of the through-portion 2 is adapted for initial insertion into the hole in the wall of the main 70 and then for subsequent radial outward expansion so that its surface sealingly engages with the edge of the hole. An expander 4 is provided for location within the end 6 of the through-portion 2 and is adapted in a first position to permit initial insertion of the end of the through-portion into the hole and on movement to a second position to cause expansion of the end 6 into engagement with the edge of the hole.