These 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 ST joints), a flask (with 24/40 ST top and 19/22 ST lower joint), and a graduated tube (with 19/22 ST joints). All columns have venting dimples. The 500mL complete apparatus includes a 10mL tube. The 1000mL complete apparatus has a 25mL tube. For replacement Snyder columns, see Cat.No. 1-2158-3CO.