These are also my favorite kinds of strands, but it took me a bit to catch on too. I also found class, party, and litter and was so confused, but once I found crop it clicked for me.
A bel is, in fact, ten decibels. It's one of the weird units where one of the original unit turned out not to be the best granularity, and so it's better known with a metric prefix already on it, like kHz.
