QUANTIFOIL is a perforated support foil with pre-defined hole size, shape and arrangement that has advantages in electron microscopy (EM) or low-energy electron point source (LEEPS) when compared with conventional holey film. QUANTIFOIL with circular holes is used in cryo-electron tomographic reconstruction. The roundness of the holes is advantageous with respect to the formation of an ice layer of constant thickness. A foil with ~1.2 µm circular holes and a spacing of ~1.3 µm between the holes. Smaller holes are designed for magnifications of 50,000x or higher. Grid: Gold. Mesh: 200 .