I personally use https://www.amazon.de/Mammut-Amino-Liquid-Flasche-Pack/dp/B01M0M12VS/ref=sr_1_5?crid=LGXT0V1X6YSO&keywords=mammut+amino+liquid&qid=1688664335&sprefix=mammut+amino+%2Caps%2C110&sr=8-5 and picked it mainly because it was the cheapest available on Amazon.
I personally use https://www.amazon.de/Mammut-Amino-Liquid-Flasche-Pack/dp/B01M0M12VS/ref=sr_1_5?crid=LGXT0V1X6YSO&keywords=mammut+amino+liquid&qid=1688664335&sprefix=mammut+amino+%2Caps%2C110&sr=8-5 and picked it mainly because it was the cheapest available on Amazon.