Our PG/VG base mixes is sourced from USA-based USP compliant manufacturers and is the exact source we use to dilute our PG and VG nicotine products. Our PG/VG base mixes are perfect for further diluting our nicotine base to your desired nicotine concentration. 15 and 55 gallon aliquots ship with 3/4" and 2" NPT spigots for draining - our gift to you! As always, each lot of PG/VG base mix ships with its respective certificate of analysis, guaranteeing the USP status of this ingredient, and can be used to tag its individual lot number to such data. View an example of our most recent certificate of analyses here. Don't settle for an ingredient in your DIY arsenal that you are not comfortable using; choose a GC/MS validated chemistry! We recommend storing PG/VG base mixes in a cool, dark, dry environment. PG/VG base mixes are extremely hygroscopic, so make sure to store in a relatively dry environment with the cap SEALED TIGHTLY. If stored correctly, VG can have a shelf life exceeding one year.