Flat Bottom Micro-Insert 250ul 300ul, clear glass, size: 31*5mm(250ul) suit for 8-425 vials; 31*6mm(300ul) suit for 9mm, 10-425, 11mm vials. To meet the needs of microvolume feeding, micro-inserts of different volumes and configurations are available to convert the sample vial from full capacity to a defined volume in one simple step.