According to DIN EN ISO 4797 and in addition to DIN standard, with inscription label.

Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks
Flasks flat bottom, NS joint
NS jointed flat bottom flasks