The two piece cover with the cap will work with a shorty drip tip or the little rubber mouth piece on them. The fit is tight around the top of the ce2 but you will get air
through the window cutouts. to refill, i unscrew the ce2 and cover from the battery together, pull the ce2 about halfway out
through the top, take off the drip tip and fill. after it is filled, push the ce2 back in to about where it was and screw the ce2 and cover back on to the battery together, then replace the drip tip. when you use a drip tip, it stretches the plastic a little around the top of the ce2, which makes it a little harder to get out of the cover. the easiest way to do it is push it back through from the top with the connector end of your battery. once the drip tip end is stretched out, it gets a little harder put the cover back over it, so using the rubber mouth piece might work better. the only warning i have is do not do what i did and try to pull the cover off while the ce2 is still partially screwed in because it will pull the tube off and your battery will get a
juice bath