Guillaume Rosin

Note: im a beginner violinist and ive only used 2 rosins before.
1 no-brand cheap rosin. And the Bernardel rosin.
The Guillaume really does make a big difference to the sound. It sounds deeper, darker and richer, more romantic.

However, in my climate (24c indooors, 50-60% humidity) it is sticky already out of the cloth, unlike Bernardel which is a tiny bit sticky but still "dry".
So ive had enormous difficulty actually applying this rosin and getting it to rub off on the hair, it feels like the rosin just glides and the hairs never grip to rip off the much needed fine dust.
Compared to the Bernardel which feels like sandpaper when applying, so you really feel and know how much youve applied and that it sticks in the hairs.
This is all with pre-roughing the rosin ofc.

I actually had to put the Guillaume in the fridge for 10min, to cool it down and make it more "dry", to get it to apply properly on the bow hair.
Your mileage may vary.

It produces a gorgeous rich deep tone, but can be a nightmare to apply.
What takes 2 strokes with the Bernardel takes 20 strokes with this.
(Now i understand why Ray Chen sits in his videos furiously rubbing this rosin on his bow for 15 solid minutes lol).

I personally have been in the luthier shop in Bruxelles, Belgium. Guillaume are well known for their rosins. The quality of the rosin of Thomann is the same as if you bought it directly from them.

works any string instrument, would say only not for D. Bass.

It has a really powerfully grip so it's recommended for players that search for a direct and brilliant sound. Also doesn't leave a lot of dust, that's a great thing to keep your instrument and bow clean.

What to say, it is a rosin, a good one so no magic in it, as it is a rosin:) good to have for your bow, but wont play instead of you. You can have better for less money, or you can pay a lot more it depends on you. As for rosins goes, this one is from Brussels so probably work the best in Brussels and places with same climate, as humidity and temperature are related with performance. Play well and in tune please any rosin will do the job fine if its made yor your climate.