Our water jerrycans with tap for foodstuffs are made of the highest grade HDPE and of course free of BPA and other additives. Because the jerrycan is transparent you can easily view the liquid level. You can unscrew the tap at the bottom of the jerrycan. This will leave you with an opening of 3/4" with internal BSP thread on which you could mount other accessories.
The screw cap is attached to the neck. We advise not to fully tighten the screw cap of the jerrycan when you are going to open te tap. If you do not fully tighten the screw cap, this ensures better aeration and an even flow of the liquid.
In addition, always make sure that you clean the jerrycan well after use and let it dry before you store it for a longer period of time. This prevents fungi from growing and other unwanted bacteria.