However, Faber-Castell has caused quite a mess in the Refills, I think. They are namely in a previous administration (Circular box, 25 ml) and a newer (visually smaller, rectangular box, 30 ml). Both have the same Darreichungen Faber-Castell product number (154 907 in the specific case).
In the product description on this page states: 30ml, the box shown is rectangular, ie it describes the recent administration. But sent I got the senior administration with 25ml. So you should first consider what you get sent.
The Refill works - as indicated - at various Textliner types, in particular the general standard Faber-Castell 1548 (TEXTLINER 48) and the Faber-Castell Grip 154 304 - (TEXTLINER 1543).
Overall I am very happy with the product. It does exactly what I expected from him. According to manufacturer's information rich 30 ml for at least 8 refills. As far as I'm not yet to confirm it can.