Download our free spring rate calculator app for the iPhone and Android. Search for Profender in the app store or Android market.
http://itunes.apple.com/app/id488522451?mt=8&affId=1578782
https://market.android.com/details?id=com.profender.calc&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5wcm9mZW5kZXIuY2FsYyJd
http://itunes.apple.com/app/id488522451?mt=8&affId=1578782
https://market.android.com/details?id=com.profender.calc&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5wcm9mZW5kZXIuY2FsYyJd