The "e" in ProfiLux 4e stands for essential.

The ProfiLux 4e features the same high degree of quality and reliability as the flagship ProfiLux 4.

With ProfiLux 4e, users who do not – or not immediately – need all the features of ProfiLux 4 are offered a more affordable alternative to ProfiLux 4 without sacrificing the essential ... Learn more here:
https://www.aquariumcomputer.com/…/profilux-aq…/profilux-4e/

Available at GHL shop here:
https://store.aquariumcomputer.com/e...ofilux-4e.html