The RLM-18CX calculator is an extensive set of tools and enhancements inspired in the real HP-18C calculator. It works in the same way, with all the functions of the real calculator (except time & alarms) but, with an enhanced design, menus and features to bring up the most of your iOS device.

Once the app is installed for the first time in your device, you have 30 days of a fully functional "Free Trial". After, to continue using the app, the store view is shown asking to do a one time payment for lifetime.