It protects the core from breaking even from the strongest pressure at any angle during writing. When a strong writing pressure is applied vertically to the paper surface, the spring built into the shaft allows the core to escape upward and prevent it from breaking. When a strong writing pressure is applied diagonally, the metal part at the tip automatically comes out to wrap and guard the core. The two mechanisms operate by automatically adjusting the distribution according to the angle and strength of the applied force. By installing a part that guides the sharp core inside the shaft, even a short core will not shift and become clogged. By using it without worrying about broken or clogged cores, users can concentrate on writing with peace of mind in important situations such as daily study and tests. "Delguard" provides the best performance.