The T12.5SDS + masonry drill bit is designed and produced specifically for the Tetra M12 ladder tie bolts.
When we first started developing and testing the ladder tie bolt, we established quickly, that in certain substrates, an M12 drill bit was just too small, and the M13 was too big. So we looked to find existing 12.5mm bits. The options available, were cost prohibitive, so we developed our own to ensure a cost effective product which was hard wearing.