STA-KOOL 390, White acrylic sealant flexible roof patch is an extra tough, flexible repair compound designed to patch splits, cracks and holes in roof surfaces. This water-based patch dries quickly to a non-tacky surface which offers great adhesion to all coatings applied over it. It is designed to repair cracks and holes up to 1 in width. STA-KOOL 390 should be used with universal patching fabric. STA-KOOL 390 remains flexible while it expands and contracts with your repair, making it ideal to use with all STA-KOOL products.Stops leaksLong-lasting flexible repairUse with reflective coatingsUse with reinforcing fabric