This glue is not only clear, pure and consistent bottle after bottle, but also designed to "wick" better into balsa wood for the strongest bond possible. Each viscosity (CA, CA+ and CA-) has been tested and formulated to achieve the maximum penetration required for its specific application.
Cyanoacrylates, commonly referred to as "CA", are moisture-activated adhesives stabilized with acids. Water overpowers the small amounts of acid found in the CA, so that when CA is applied to a part, moisture from the surface of that part and from the atmo sphere cause the CA to form a solid, or bond, in seconds.
Some surfaces, such as plywood, spruce and balsa, have a natural acidic content which may blend with the acidic stabilizers in the CAs, overstabilizing them. This could cause CA to take longer to cure or to not cure at all. It is for this reason that Pro CA is a "surface insensitive" CA. This makes the glue adhere well to all surfaces, especially balsa wood. Sometimes activator may be required to speed the glue's curing process and increase the strength of the bond.