They are prefilled and you keep them in the fridge; ours were about the size of lemons. You screw the end of the tubing into the end of the picc line, unclamp, and depending on med / dose it varies on time to run. Ours took about 45min as long as we took them out of the fridge a couple hours early to let them warm up. <br><br>Here is a link: <a target="" title="" href="http://www.iflo.com/prod_homepump.php">http://www.iflo.com/prod_homepump.php</a> <br><br>There are a couple other brand names for these kind of abx, they work essentially the same way. <br>