It's a premix .40:1, if that's what your to operates on don't add anything. Kind of the point of buying premixed fuel .
mix it yourself you can make almost 8 gallons for the price of one gallon
Green can is 40:1, red can is 50:1. Refer to owners manual to determine which one to use. My husqvarna chainsaw uses 50:1 and my poulan uses 40:1 so you have to check.
It was very useful! Gets the job done