Premium Borosilicate 3.3 Glass Body – 250mL capacity, clear graduated markings, GL80 screw mouth design, excellent chemical resistance and thermal stability, perfect for vacuum experiments, buffer storage and lab reaction applications Precision Pressure Gauge & Control Valve – Equipped with a vacuum pressure gauge and adjustable control valve for real-time pressure monitoring and fine vacuum regulation, helping you accurately maintain the required vacuum environment Tight Sealing & Durable Structure – Sealed GL80 blue screw cap with matched fittings, good air tightness to sustain stable vacuum conditions; sturdy construction for repeated lab use, overall height approx 105mm for easy bench placement Clear Visibility & Easy Operation – Transparent glass for direct observation of sample status; easy to assemble, clean, a practical lab vacuum reaction bottle for daily scientific research and teaching experiments Wide Laboratory Application – Ideal for vacuum filtration, degassing, solvent storage, chemical synthesis, microbial culture preparation and other chemistry & biology lab research work