Our micro-insert products are available in conical bottom, flat bottom, with Mandrel Interior's and Polymer Feet forms. They are designed to fit several sizes of chromatography vials such as ND8, ND9, and 8-425 threaded vials. Tisch Scientific 250 µL Micro-Insert, 31 x 6 mm for 9 mm Vials, Conical Bottom, 100 Pack, CV2046