Standard opening vials require 5mm inserts, Wide opening vials 6mm Inserts Shop Fisherbrand™ Micro-Insert, Clear Glass, for crew neck vial, 13-425 thread at Fishersci.be Fisherbrand™ Micro-Insert, Clear Glass, for crew neck vial, 13-425 thread conical,0,5 mL Volume,<9 µL residual volume,40 mm height Fisherbrand™ Micro-Insert, Clear Glass