170N-Stiffnuts-27-x-32-Kit-6-Piece-Monument-170N-p-The-Monument-170-has-been-especially-designed-for-removing-stiff-backnuts-from-awkward-placed-taps-&-to-make-tap-installation-a-more-rapid-process-this-tool-is-for-1-2-inch-BSP-&-3-4-inch-BSP-taps-The-Monument-170-tool-stays-in-position-on-the-tap-tail-so-can-be-used-with-one-h&-&-uses-mechanical-advantage-of-the-thread-of-the-tap-tail-to-remove-stiff-nuts-p-p-Ideal-for-Monument-stiffnuts-27-mm-&-32-mm-&-for-1-2-inch-B