Flask Boiling with joint 500ml, socket size 24/29, round bottom, interchangeable joint, single neck, borosilicate glass-EIS-CH0404I offers a thoughtfully designed, durable resource for hands-on learning. Made of high quality, heavy duty Borosilicate glass 500ml capacity Single joint with 24/29 size socket Stands 6.5" tall, neck measures 1.3" wide, and bottom diameter measure 4.5" Perfect for any science or home laboratory 500ml capacity boiling flask made of high quality, heavy duty borosilicate glass. Single, interchangable joint with 24/29 size socket. No stopper included. Flask measures 6.5" tall, and has a neck measuring 1.3" wide, and a bottom diameter measuring 4.5". Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C.