I found a wonderful bag at this website
They have both a 2 quart and 4 quart silicone bag.
I also got tubing from them, the bags are translucent, so you can see how much you have taken.
I used one for almost a year, I just got a second one.
What I did was order two bags, one piece of 6 foot tubing, cut it in half, installed a Y connector, with clamps on each bag.
I also have two pieces of tubing, 6 foot each with a wheel connector, to see the flow.
I can fill one bag with warm water, the other bag with hotter water and then open both clamps. I have a clamp close to the nozzle to shut off the flow.
I have found this to be the best way for my enemas ever. I can fill both bags, get two, maybe 3 fillings before refilling again.
I just love the way it feels, water flowing in, filling me up and then I get to empty to get filled again.