We have a "Nuki box" hanging on the lock. I don’t find it nice, but we have gotten used to it. Meanwhile, there is a new development from Nuki, where there is no longer a box attached. Only a round stainless steel attachment on the key. That looks significantly more elegant. How that works technically? No idea. In the box of the last model are mainly the batteries or accumulators, and allegedly the new one is even more powerful than the old one. The Nuki does not work 100% reliably for me, but you can manage with it. I find it too annoying to get familiar with the software – and it often doesn’t work intuitively. Nevertheless, I would buy such a device again if it “were no longer there.” The greeting by the self-opening door is always a pleasure for me – especially when I’m carrying something in both hands.