These 500mL PYREX® Kuderna Danish Concentrators are supplied with Keck clamps instead of spring hooks. The complete apparatus consists of a 3-Ball Snyder column (with 24/40 Standard Taper joints), a 500mL flask (with 24/40 Standard Taper top and 19/22 Standard Taper lower joint), and a graduated 10mL tube with an outer 19/22 Standard Taper joint. The tube graduations go from 0 to 2mL in 0.1mL increments and from 3mL on in 1.0mL increments. All columns have venting dimples. For replacement Snyder columns, see No. 2158-3CO.