Rugged spherical jacketed reaction flask with Duran, flat, ground flange with O-Ring groove, for use with 6517 Quick Release Clamp. Each flask is supplied with one CAPFE O-Ring (PTFE encapsulated silicone O-Ring). 12L and larger are supplied with reference graduations. Inlet/outlets available with either tangentially sealed 28/15 o-ring ball joints or with #11 Ace-Thred connections for use with 3/8in ID tubing. See 6528 and 6529 reaction heads.,/P.