Our standard answer is to use the tip that allows you to inject the tree and is the best one for you and the tree. We understand that trees come in all sizes and varieties so we have an assortment of injection tip designs. Our specialized Quick-Connect Injection Tips are designed to work with trees of various bark thickness and to place chemical precisely where each tree’s unique vascular structure can best use it. And remember, no drilling is required with any Quick-Connect Injection Tip. For more information, click here.