Standard opening vials require 5mm inserts, Wide opening vials 6mm Inserts Shop Fisherbrand™ Micro-Insert, Clear Glass, for small opening vial at Fishersci.at Fisherbrand™ Micro-Insert, Clear Glass, for small opening vial flat bottom,0,2 mL ,<8 µL residual ,31 mm height Fisherbrand™ Micro-Insert, Clear Glass, for small opening vial