The Emerald Glue is carefully tested to ensure the highest quality and safety standards available for eyelash extensions. This eyelash extension glue is to be used by trained professionals only. It offers a superior bonding performance of 1 to 2 seconds and holds on for 4 to 6 weeks before a refill is needed. It complies with all Health Canada regulations. Its Ideal humidity levels are 45% to 65% for the best results.