The bypass lopper is for living wood. Its two curved blades pass each other like scissors, making a clean slice that does not crush the branch tissue. The cut heals quickly. The plant stays healthy. This is the lopper you reach for when you are shaping a rose bush, thinning an apple tree, or cutting back perennials in spring.
The anvil lopper is for dead wood. A straight blade comes down onto a flat anvil surface, concentrating force at a single point. Dead wood is brittle and hard — it resists the sliding action of bypass blades but yields to the crushing geometry of an anvil. This is the lopper for clearing storm damage, removing dead branches, and cutting back anything that has already dried out. One tool cannot do both jobs well. This set gives you the right tool for each.