Formally US-56, Safale US-05 is a strain of yeast that creates that classic American profile of clean malt, crisp taste, low diacetyl, and ability to ferment in a wide range of temps. Look for Safale US-05 to be the next popular dried yeast.
This is marked as directly pitchable yeast and there are no rehydration instructions.
Some instructions for rehydrating yeasts: Suspend yeast in 4 oz of warm water. Do not stir. Let stand for 15 minutes. Stir gently. Add an equal amount of wort to your solution. Cover, let sit for five minutes, and pitch.