New individual LIQUI-CULT Test Kits are used to detect microbial growth in fluids including diesel and gasoline. This simple to use test determines the type and degree of infestation. Easy to follow instructions and a color comparison chart included with the kit. Simply add small sample of fuel to the provided liquid and wait for 30 to 72 hours for results. A preventive maintenance must. * Special order. Item may take seven business days before it is shipped