Walker Ultra Hold Glue is made specifically for hair extensions, especially Perfect Locks hair. This adhesive can easily provide up to 4 weeks of super-strength attachment. Anyone who has had problems in the past getting a long-lasting bond using other adhesives will LOVE the strength and security offered by this product. Walker Ultra Hold Glue is made from a waterproof, "non-yellowing" formula and comes with a handy brush-on applicator for clean application.