The Assure Pro control solution (Levels 1 and 2) works on the Assure Pro blood glucose monitoring system. The Assure Pro control solution keeps the meter and test strips operating properly by calibrating the meter. Test the meter and strips with control solution whenever you suspect inaccurate results, upon opening a fresh package of testing strips, when using a new meter, or after replacing batteries. Two bottles of solution - Levels 1 and 2 - are are packaged together in one box.