This is BROWN version of ISOTONITAZENE. Which lower cost for production. We don't know if it's weaker than the white or the yellow versions. You need to try it by yourself. Please be careful as always. If you prefer our white version of ISOTONITAZENE, please go to the following link -
https://tgc-rc.ru/isotonitazene

Isotonitazene is a benzimidazole derived opioid analgesic drug related to etonitazene, which has been sold as a designer drug. It has only around half the potency of etonitazene in animal studies, but this still makes it a similar strength to fentanyl and its analogues, and consequently isotonitazene can be expected to pose a significant risk of producing life-threatening respiratory depression, as well as other typical opioid side effects such as sedation, itching, nausea and vomiting.

Isotonitazene (obtained from an online vendor) was fully characterized in November 2019 in a paper where the authors did a full analytical structure elucidation in addition to determination of the potency at the μ-opioid receptor using a biological functional assay in vitro. While isotonitazene was not compared directly to morphine in this assay, it was found to be around 2.5x more potent than hydromorphone and slightly more potent than fentanyl.