Rugged cylindrical reaction flask with Duran, flat, ground flange and o-ring groove, with water/steam jacket. Jacket inlet/outlets are available with either 35/25 o-ring ball joints (sealed tangentially) or with Ace-Thred connections. For use with 6517 quick release clamp. Flask supplied with one CAPFE O-Ring for Duran flange. Plain silicone o-rings are also available. 10L and larger sizes (only) come with reference graduations.