These are Replacement M6 Stainless Steel T-nuts for the any hydrofoil that uses the M6 T-nut including Takuma, Naish and others These are hard to get replacements that we now have in stock. They are sold each so if you need a set of 4 make sure to buy 4 of them. Watch the video below for our testing of the M8 version against the brass version. Here are the total dimensions of this part: Track width: 8.5mm Total width: 14.9mmTotal length: 23.9mmTotal height: 6.20mm