MAM soft bottle spout

Has anyone used one of these before?? I got one as part of the MAM bottle bundle I got when baby was first born - he’s now 10 months old and I’ve found this attachment that I’ve never used! Can’t for the life of me work out what you use it for, google seems to say different things and also has bad reviews as people say it’s really hard for babies to get any liquid out when using them. I can’t even see a hole in the top like you have in the normal teats so how does it even work?? Help a girl out I haven’t got a clue what to use it for 🤣🤣