The Quantifoil Holey Carbon Grid provides an ideal, ultra-flat support for biological samples in cryo-electron microscopy (cryo-EM) techniques. This grid features a precise R 1.2/1.3 hole pattern, with 1.2 µm hole diameter and 1.3 µm interspace, applied on a robust 300 copper electron microscopy mesh. The uniform circular holes and a carbon film thickness of about 12 nm ensure optimal particle dispersion and consistent ice thickness, crucial for achieving high-resolution data. Crafted from copper, this mesh offers excellent conductivity and inherent stability for reliable imaging. They are indispensable for obtaining high-quality data and clear visualization, contributing to enhanced resolution and reproducibility in structural biology research. This product is supplied in a convenient 50-pack, providing ample supply for demanding experimental needs.