I made the mistake of paying $50 for one from Snap On and found that it was a very cheap tool made in Tiawan for a high price. You can buy one for less:
http://www.sjdiscounttools.com/lis36200.html but it will only allow you to install the keepers. To remove the keepers, get a 3/4" piece of PVC pipe about a foot long and cut a U shape in the end. (I cut an X in a tennis ball and stuck it over the other end so it won't hurt your hand when you push down.) Put the PVC on the spring cover, push down on the tennis ball and stick a magnet in the U shaped hole and remove the keepers!
http://www.sjdiscounttools.com/lis36200.html but it will only allow you to install the keepers. To remove the keepers, get a 3/4" piece of PVC pipe about a foot long and cut a U shape in the end. (I cut an X in a tennis ball and stuck it over the other end so it won't hurt your hand when you push down.) Put the PVC on the spring cover, push down on the tennis ball and stick a magnet in the U shaped hole and remove the keepers!