If you want decent flushes with zero chance of contamination then you found the spot. My golden teachers blew up off there substrate and jars both grain and bed cakes!!
These substrate jars are perfect. They were sterilized properly and filled with great materials. No problems with contamination. Your spores will feast on this and grow beautifully. I Highly recommend it to help you get that grow running.
Everything arrived in a timiley manner 5 stars