These props are perfect for those building with a T mount or 5mm shaft in ultralight or toothpick projects. The diameter is 4' (102.2mm), pitch is 2.3', and they have 3 polycarbonate blades. The hub thickness is 5.5mm, and the shaft hole is 5mm and 1.5mm T-mount with an optional insert. They come in a pack of 4 (2 CW, 2 CCW), weighing 1.98g or 2.1g with the adapter.