The Energizer 384/392 is a high performance multi-drain watch battery. Multi-drain watch batteries perform equally well in low-drain and high-drain watches.
The size 384 and size 392 watch batteries are identical in size and voltage. The 384 is optimised for "low drain", while the 392 is for "high drain" applications. "High drain" means the bursts of power required e.g. when you press the light button on your watch. Because the 392 does everything the 384 does, and more, Energizer has streamlined production and now only makes one battery.