Susan.....I'm not positive on this' date=' but I believe if you contact the pump companies and ask to meet with a representative, they'll have someone contact you and then you can sit down and actually take a look at the pump(s) and their features and decide from there. Good Luck!
Thanks - I forgot that. I have another year to go anyway with no complaints on my 522, really. I did look at the videos for the Ping and that was really interesting.