It accommodates 4 teeth if you happen to start at one end of the eccentric travel and finish at the other. However, it's pretty much pure luck if your chain length happens to work that way. I'd generally work on the assumption that you can manage a two-tooth spread on the rear (e.g., 16+18). I set up a couple friends with Eno hubs and we experimented with how much gearing range we could manage. Only on one bike did we have the chainstay length that gave us a 3-tooth range or more. If you want to play around with half-links you can increase the range (if you aren't lucky to begin with), but a two-tooth spread on the rear is actually quite a lot of gearing range.