Fabricated from borosilicate glass with walls tapered inward toward bottom to allow operation with smaller volumes. 250 mL size supplied with #25 Ace-Thred center neck and three 14/20 side necks. All other capacities supplied with #36 Ace-Thred center neck and three 24/40 side necks. Use 7506-10 Bushing and O-Ring in #25 Ace-Thred, 7506-12 Bushing and O-Ring in #36 Ace-Thred to form a leak-tight compression seal with all 9814 Horns with groove and 9852-41 or 9852-45 Slide Adapter. Stated capacity is without horn.