Laboratory rubber stoppers #0–#13 (25 mm tall) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/rubber-stoppers/  (CC BY 4.0)
Basis: Standard US laboratory stopper sizes: top and bottom diameters, 25 mm tall; drawn as a straight taper (loft) between them
Catalog version: 2026-10-20

Sizes: see table below
- Stopper number → top / bottom diameter (mm): #0 17/13, #1 19/15, #2 20/16, #3 24/18, #4 26/20, #5 27/23, #6 32/26, #6½ 34/27, #7 37/30, #8 41/33, #9 45/37, #10 50/42, #11 56/48, #12 64/54, #13 68/58; all 25 mm tall.
- Each file is a solid truncated cone between those diameters; one- and two-hole versions of the real stoppers take 5–7 mm tube.
- Pick the stopper whose mid-diameter is about 1 mm over the opening: 16 mm test tube #0, 20 mm #2, 25 mm #4/#5, 28 mm soda-bottle neck #6.
- The table gives the opening range each number seals.
- One file is a #4 bored through on its axis at Ø4 (stopper-4-bore-4): the stopper of the test-tube marble engine, with a 4 mm OD brass tube through it. The bore is my geometry, drawn at the tube's OD.

number  top_mm  bottom_mm  height_mm  fits_opening_mm
#0  17  13  25  14–16
#1  19  15  25  16–18
#2  20  16  25  17–19
#3  24  18  25  19–23
#4  26  20  25  21–25
#5  27  23  25  24–26
#6  32  26  25  27–31
#6.5  34  27  25  28–33
#7  37  30  25  31–36
#8  41  33  25  34–40
#9  45  37  25  38–44
#10  50  42  25  43–49
#11  56  48  25  49–55
#12  64  54  25  55–63
#13  68  58  25  59–67

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Bung — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Bung
- Wikipedia: Cork (material) — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Cork_(material)
- Long Earth Society: Engine builds (videos and write-ups) — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 16 parts): https://xemstudio.com/files/hardware/rubber-stoppers/index.json
API: https://xemstudio.com/api/geometry?object=rubber-stoppers