The product info says this"
² Specific Gravity applies to a mixture of 1 lb of extract with 1 gal of water. For 'brewer's points', use the final two digits of the figure."
Your product should be similar. Somewhere it should say (a pound with a gallon of water will give you "X" in Gravity) or PPG(points per pound per gallon) ie a ppg 1.040 or 40 meaning a pound of extract with a gallon of water will give you a gravity reading of 1.040