Titebond Instant Bond Medium - Jet Black is an ethyl cyanoacrylate adhesive that provides professional-strength, permanent bonds to most common materials. This rubber-toughened formula is extremely impact-resistant and ideal for hiding imperfections, repairing cracks, and filling knots/voids in wood materials. With a longer working time of approximately 40 to 60 seconds (compared to other cyanoacrylates), it allows for precise application for complex projects.