These are all-metric threaded M6 or M8 T-slot bolts and have 18 x 12mm heads and are zinc plated. They are a direct fit into our Toolmate T-Track. Both threads are available in 3 lengths: 25mm, 50mm, or 75mm. The metric thread opens up a wider range of options, especially with other easily available metric-threaded fittings. Supplied in packs of 10.