The only difference is single or dual solar panels. The dual panel unit works better in warmer areas. The solar panels only power the aspirating fans to keep the air moving in the units. You can change a standard into a pro by changing the top. And yes they both work with the Access unit.
Hello Craig, George and Ledrak are correct. The only difference is the single and double solar panel. The dual panel is recommended in sunny areas to provide more power to the fan. The 5in1 sensor is compatible with the Access. It will not matter if you use the PRO or PRO+ upgrade. Please let us know if you have any other questions. Thank you.