I googled, so I could get the correct info about them.

They are called Kala's Magic Spout 28mm pk.
I bought a bottle of water at the shops the other day (all of a sudden we were all boiling and parched), all you do is remove the plastic ring left behind by the normal lid, and add the kala one.
Myself, my DS (nearly 3), and my DD (9 months) all shared the same bottle of water with ease, and with no spilling.