PYREX 250mL Round Bottom Boiling Flask with Short Neck and 29-42 Standard Taper Joint – 4321-250

The PYREX 250mL Short Neck Round Bottom Boiling Flask is a durable laboratory glass flask designed for heating, boiling, distillation and chemical solution preparation. Manufactured from No. 7740 borosilicate glass, it features a short neck with a 29/42 standard taper joint for connection to compatible laboratory apparatus. Its round-bottom design promotes uniform heating, making it suitable for research, pharmaceutical, analytical and educational laboratories. Key Features - 250mL Capacity: Suitable for small-volume laboratory heating, boiling and chemical preparation. - Borosilicate Glass: Manufactured from PYREX No. 7740 glass for excellent chemical durability and thermal resistance. - Round Bottom Design: Promotes uniform heat distribution during controlled heating. - Short Neck: Compact construction suitable for laboratory glassware assemblies. - 29/42 Standard Taper Joint: Full-length outer ground-glass joint for compatible laboratory equipment. - Controlled Wall Thickness: Provides a balance between thermal shock resistance and mechanical strength. - Heat Resistance: Normal working temperature of 230°C. - Chemical Durability: Resistant to many commonly used laboratory chemicals. - Dimensions: Approximately 83mm outside diameter and 140mm overall height. - Reusable Construction: Suitable for repeated laboratory applications. Parameter Specification Brand PYREX Manufacturer Corning Product Code 4321-250 Product Type Laboratory Boiling Flask Nominal Capacity 250mL Material No. 7740 Borosilicate Glass Flask Shape Spherical Bottom Type Round Bottom Neck Style Short Neck Top Style Standard Taper Joint Joint Size 29/42 Joint Type Full-Length Outer Standard Taper Joint Outside Diameter Approximately 83mm Overall Height Approximately 140mm Normal Working Temperature 230°C Thermal Resistance Thermal Shock Resistant Chemical Resistance Excellent Chemical Durability Glass Colour Clear / Transparent Stopper Included No Reusability Reusable Sterility Non-Sterile Manufacturer Quantity per Pack 1 Piece Manufacturer Quantity per Case 1 Piece Compatible Kit Series Corning Organic Chemistry Kits 6949–6949K Applications Laboratory Heating, Boiling, Distillation, Chemical Reactions and Solution Preparation