It is the No. 1 - PERM (Curler) Solution in the Prolash Eyelash Lifting Set. THE SOLUTION IS 6 ML. THE DIFFERENCE FROM STANDARD 5 ML BOTTLES ON THE MARKET IS THAT PROLASH BRAND SPECIAL BOTTLES ARE 6 ML. 40 USAGES. THIS WILL REDUCE YOUR COST PER APPLICATION. THE BOTTLE MOUTH WIDTH HAS BEEN DESIGNED WIDE ENOUGH FOR ONLY THE BRUSH TO ENTER IN ORDER TO ALLOW A MINIMAL AMOUNT OF AIR. THIS MINIMIZE THE RISK OF DETERIORATION OF THE SOLUTION. It is offered for sale for Beauty Salons and Academies who want to try the quality we provide in the set. It acts as a stabilizer and makes eyelashes look more vibrant with the vitamin E it contains.