Base B4 is our version of the IUCr standard “brass pin” style base commonly used in small molecule crystallography, modified for use with MicroMounts™ and the MicroRT™ system. Unlike other 3 mm / 1/8″ diameter bases, our B4 has a smaller diameter central hole to tightly capture the stainless steel rods of MicroMounts™, and an extension to capture our MicroRT™ capillaries. Use for both room temperature and cryocrystallography applications.