Abstract: New devices for providing an indication to a nursing mother as to whether a baby is receiving milk during a breastfeeding session. Milk expressed from the mother's breast is caused to flow through a transparent passageway part of a nipple shield, disposed in in a position where it visible to the mother or a third party, before being supplied to a nipple of the device, from which the baby is enabled to suck. The device therefore provides an indication that the infant is receiving milk from the mother's breast. The visibility of the passageway is achieved by routing the passageway through a region of the device whose line of sight with the mother is not obscured by the baby when feeding, such as towards the periphery of the base layer of the device. The device passageway may also comprise a valve, and details of such valves are disclosed.