These PYREX replacement Kuderna-Danish flasks have s a 24/40 outer Standard Taper upper joint and 19/22 inner Standard Taper lower joint.
- Cat. No. 2158-250FO includes a pair of stainless steel springs.
- Cat. No. 2158-500FO includes a pair of stainless steel springs and two sizes of Keck clamps.
- Cat. No. 2158-1LFO includes a pair of stainless steel springs.