These two SPI Supplies Brand TEM grid storage boxes are our most often asked for grid storage boxes. The original box was known worldwide as the SPI Slide-A-Grid Storage Box and the new Twist-A-Grid TEM grid storage boxes is being widely accepted an improvement in design because of the stability feature. Each box holds either 100 or 50 3.05 mm TEM grids in a combination of number/letter coded compartments. Each box is accompanied by a record card for the convenient logging and indexing of your stored (or waiting-to-be-looked-at grids). So far as we know, this box is compatible with virtually all 3.05 mm (e.g. nominally 3 mm) TEM grids, including the unique SPI Silicon Nitride Membrane Window Grids.