Please note that this PRO version is only a key which unlocks the PRO features of the free version. It cannot be started itself.
For a full description, please check "KMS Speedometer" on Google Play.Here is a link: https://play.google.com/store/apps/details?id=com.kmsengineering.kmshud
Please also make sure KMS Speedometer works good for you before purchasing the PRO version.
Just Simple Speedometer(HUD) with GPS.