It is true that semi-rigid fibreglass sheets are the best for acoustic treatment, especially those that you mentioned before- Owens-Corning No. 703
This material is a standard in the USE and in Canada too.
I doubt it if you can find these materials in Israel and in fact, it is unnecessary because similar products of other companies, including those in Israel, are generally the same and will do the job just fine (as long as you use the right density for the right job)
whether it is fiberglass sheets or rockwool sheets it doesn't really metter although some will say that fiberglass is a better material. But than again, they both do the job just fine if you know how to install a nice acoustic treatment in your space.
Bare in mind that these materials can be hazardous to your health so work carefuly, using rubber gloves and air mask and make sure to wrap them with some cloth before hanging on the walls.
I personally like to work with Paz.
Here is the website, you'll find there all the information that you need .
I'm sure that you'll find some other companies in Israel.