Stanley FatMax® Chalk Powder is specially formulated for good adhesion and high visibility. Its weather-resistant formula will not fade or bleed in a wet environment. It also prevents chalk from clumping inside the chalk reel, meaning it can still be used if soaked with water. Suitable for both interior and exterior use. It is specifically packaged in a square bottle which is designed to not roll off work surfaces. Ref: UTTK3795