Ground joints are very common in laboratory glassware. Sometimes it’s not completely clear to users how to determine the size they need, so here’s some explanation for a ground joint NS29/32;

NS stands for “NormalSchliff”
29 says 29 is biggest diameter A
32 is length B of the grounded part. So in short it’s NS A/B.

It’s common to round the diameter in describing the ground joint. For instance; standard Diameters are 29.2mm, 18.8mm and 14.5mm. These will be referred to as NS29, NS19 and NS14.

Commonly used ground joints are;
NS14/23
NS19/26
NS24/29
NS24/40
NS29/32

But they are standard available from NS5/13 up to NS100/60.