Too little info as yet - I'm bullish on Merc here; they certainly have the knowledge to put as much intelligence in to the battery as Tesla, and have a MASSIVE advantage of a worldwide distribution and servicing network. They're used to shipping 2 ton hunks of metal around the globe, so this isn't an issue for them. For Tesla to enter ZA, they have to get a local partner, set up a distribution and maintenance network and then sell them.
Looks about the same size Tesla's battery? And the website also shows the wall-mount option.
Edit: Some decent English info here -
https://schlauerspeichern.de/Batteriespeicher_Datenblatt_Home_DE_EN.pdf - pretty much exactly the same size if you take the same capacities
Either way, cool stuff - competition is good.