25x150mm Rimmed Glass Test Tube with O-ring Adapter for Wide Holes
O-ring - Wikipedia
BUSY-CORNER 382 Pieces FKM O Ring Kit, Fluorocarbon 75A, 30 Inch Sizes, Chemical Resistant and Oil Resistance O-Rings for Various Chemicals, Hydraulic, Cylinders, Plumbing (Yellow Box, Brown Orings): Amazon.com: Industrial & Scientific
CG-147 O-RING - O-RINGS FOR REACTION VESSELS AND LIDS- Chemglass Life Sciences