Questions (2)  

Question: From the picture it looks like this cap could hold the needle from a needle cap or transfer cap. Is this possible? I've been wanting a female needle cap so this would be great if possible.
ArtPrimo: It would all depend on if you could find a straw that fit.

Question: Do these leak? Also, are the fills drippy?
ArtPrimo: No it doesn't leak. Yes, if you cant control it.