This is a 1 kilogram bag of quality Copper Sulphate (CuSO4·5H2O).
Copper Sulphate has been proven to have powerful anti-fungal and anti-bacterial qualities, traditionally used for the treatment of seedy toe when mixed with vaseline.
Packed in a resealable bag, simply cut along the red line to open the first time then re-seal with the zip-lock to keep it fresh and clean.
WARNING: Copper sulphate can be very irritating to skin and can do serious damage to eyes - please take care and wear gloves and goggles etc. when handling it.