A check valve and method for manufacture of the check valve. The check valve comprises a substrate and a channel in the substrate. The channel has an anchor region, a channel corridor and a valve seat region. There is an elastomeric valve mechanism in the channel. The valve mechanism has an anchor portion anchored in the anchor region, an elastomeric web portion in the channel corridor and a valve plug in the valve seat region. The elastomeric web portion interconnects the anchor portion and the valve plug. The elastomeric web portion is in a stretched state such that the valve plug is forced by the elastomeric web portion against the valve seat region to seal the valve seat region. The force of the elastomeric web portion can be overcome by operative fluid pressure within the channel to separate the valve plug from the valve seat region and thereby open the channel at the valve seat region to allow the fluid to exit the channel via the valve seat region.