250uL Micro-Insert with Mandrel Interior & Polymer Feet, 29*5.7mm, suit for HPLC vial, Economy package: 250uL Conical Micro-Insert, 31*5.7mm, suit for HPLC vial: 250uL Conical Micro-Insert, 31*5.7mm, suit for HPLC vial: 300uL Micro-Insert, 31*6mm, Clear, Flat Bottom, suit for HPLC vials