Listing is for a single row 25 slot holder. All major brands of 2x2’s should fit.  It’s 3D printed using pla plastic and will be more durable than the cardboard models offered by others. Slots prevent holders from touching eliminating scratches and maintaining the clarity of the holder.  More inserts will be available in the future allowing 2x2s and round capsules to be stored in identical looking boxes.  This will allow compact stacking and storage. Feel free to reach out for custom colorization.