Industrial grade for maximum bonding strength. The thin version wicks into tight places where flowing into and under is essential. Medium and Heavy are for semi-smooth surfaces. Gel viscosity is for filling and bonding porous surfaces. Non-whitening activator accelerates curing time. De-Bonder removes unwanted or excess glue. Glue any combination of wood, naugahyde, plastic, veneers, cardboard, rubber, ceramics, leather or vinyl. No clamping, instant set.