Anvil pruners have only one blade, which closes onto a flat surface; unlike bypass blades it can be sharpened from both sides and remains reliable when slightly blunt. Anvil pruners are useful for cutting thick branches; one can bite into the stem from one direction, swing the handle around and bite further through narrowed wood from another direction. The anvil is made of a material softer than the blade, so that the blade is not damaged when it meets the anvil. Suitable materials for the anvil are plastic, aluminum, zinc, brass, or bronze alloys. The blades are made from hardened carbon or chromium steels. The hardness of the blades is generally between 54 and 58 HRC. On an anvil pruner, proper cutting is assured even if the blade swerves slightly to the left or right during cutting. As long as the blade meets the anvil at the end of the cut and fits tightly against it, the material is separated. For this reason, the blades of anvil pruners can be ground thinner than those on bypass pruners. The LÖWE principle – a drawing cut made against a fixed support – combines a drawing cut with a pushing cut. This is possible because the blade lever and base lever are connected by an eccentric bearing. When the pruners are open, the blade is longer than the anvil thanks to the eccentric bearing. When the pruners close, the blade draws back slightly while it pushes through the material. This reduces the cutting force needed to make a cut still further. Because they crush the stem they are cutting, anvil pruners are best for use on dead wood.