Made of PCTG,they are very safe,durable and heat resistant.
Only compatible with the 50ml trigger but will be compatible with most 50ml filling machine.
When filling multiple flavors in one day most labs choose to purchase numerous oil barrels and switch barrels out with each flavor then clean all barrels at the end of the day,this procedure saves time.
This procedure prevents cross-contamination of terpenes from batch to batch.
Package and Customer Service:please contact us to refund full money or replacement if you don't like them any time and you don't need return the unit to us or amazon..