The complete apparatus consists of a 3-ball Snyder column with [ST] 24/40 joints, flask with [ST] 24/40 outer upper joint and [ST] 19/22 inner lower joint, and graduated tube with [ST] 19/22 outer joint. Tubes are graduated from 0 to 2 ml in 0,1 ml intervals and from 3 ml to capacity in 1,0 ml intervals. All columns have venting dimples. Concentrators are supplied with Keck clamps rather than spring hooks.