Abstract: A tap 2 is provided which has a body with an inlet 8 and an outlet 10, valve means to control fluid flow from the inlet 8 to the outlet 10, seal opening means 14 designed either to pierce a sealing diaphragm or to open a sealing plug and actuation means 12, 48 for actuating the seal opening means 14. The seal opening means 14 comprises a seal opening member 16 coupled to a spring member which in an initial position is in a compressed state. The actuation means 12, 48 actuates the seal opening means 14 by releasing the spring member 18 from the compressed state such that the spring member 18 then drives the seal opening member 16 to open the seal.