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Aquarium airline tubing and fittings: 3/16 in vs 4 × 6 mm, check valves, connectors and Luer barb match
What size is aquarium airline tubing, and do check valves and fittings take 3/16 in or 4 mm tube? · Standard part · basis: retailer and maker listings read (Bluviva, Perfect Ponds & Koi, Lee's, Aquaneat, Penn Plax); only the tubing ID and OD are printed, no fitting dimensions
Also called: airline tubing size, aquarium air tubing 3/16 inch in mm, 4mm 6mm airline tubing, aquarium check valve tubing size, airline tubing id od, is airline tubing 3/16 or 4mm, air pump tube diameter, aquarium air line connector size
Exact dimensions. True size, with no tolerance added.
- sizes
- 5 in table
Notes
- Two sizes are sold as standard airline tubing: 4 mm ID × 6 mm OD (metric listings) and "3/16 in" (US listings). The 4 mm and 3/16 in (4.76 mm) are not the same number, and the US listings read here do not print the OD of their 3/16 in tube, so the page does not claim the two are interchangeable; the 3/16 in value is the tube's nominal size, and Lee's calls it the ID of the tube its check valve takes.
- Fittings (check valves, 2- and 3-way valves, L- and T-connectors, splitters) are listed as 'for 3/16 in' or 'for 4 mm' tubing. No listing read prints a barb diameter, length or port size for these parts, so there are no fitting dimensions here and no files.
- A Luer barb that fits this tube: the nearest sizes in Nordson's and Qosina's tables are 5/32 in (4.0 mm ID) and 3/16 in (4.8 mm ID) tube barbs, see luer-to-barb-adapters. Silicone and PU push-fit tube sizes (including the 4 × 6 mm tube) are on silicone-tube-and-fittings.
- Not covered: pump outlet nozzle diameters, air-stone barbs and CO2 tubing, which were not read.
Aquarium airline tubing and fittings: 3/16 in vs 4 × 6 mm, check… size chart
| item | ID | OD | wall | source |
|---|---|---|---|---|
| airline tubing, metric | 4 mm | 6 mm | about 1 mm (computed, (OD − ID)/2) | Bluviva ("4/6 mm" as the usual size for most air pumps and attachments); Perfect Ponds & Koi (4 mm ID, 6 mm OD) |
| airline tubing, "3/16 in" | 3/16 in (4.76 mm, computed) | not printed | not printed | Aquaneat listing: "Standard 3/16 in" tubing; Penn Plax listing: "3/16 in" (no ID/OD split in either); Lee's: pumps that use 3/16 in ID tubing |
| L-shaped connector | for 4 mm ID tubing | — | — | Aquaneat listing (no part dimensions printed) |
| air control valve (2-way / 3-way) | for 4 mm tubing, or "3/16 in ID" | — | — | Aquaneat listings (no part dimensions printed) |
| check valve | for 3/16 in airline tubing | — | — | Lee's 12405, Aquaneat and other listings read (no part dimensions printed) |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Bluviva | Airline and fittings category: standard airline tubing 4/6 mm (ID/OD); fittings should match the tubing | web | Retailer page; numbers only |
| Perfect Ponds & Koi | H/D clear per meter airline 4 mm ID, 6 mm OD | web | Retailer page; numbers only |
| That Pet Place (Lee's check valve 12405) | Lee's airline check valve: all air pumps that use 3/16 in ID tubing | web | Retailer page; numbers only |
| Walmart listing (Aquaneat airline tubing) | Standard 3/16 in airline tubing; check valves for 3/16 in tubing; L-shaped connectors and air control valves for 4 mm ID tubing | web | Retailer listing; numbers only |
Xem scan
File coming
No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.
https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.Plain text: sheet.txt · JSON: /api/geometry?object=aquarium-airline-tubing
Fits with
Questions
What size is standard aquarium airline tubing?
Retailers list 4 mm ID × 6 mm OD (metric) and 3/16 in nominal (US). The US listings read do not print an OD.
Does a 3/16 in check valve fit 4 mm tubing?
The listings say 3/16 in valves are for 3/16 in tubing and some connectors are for 4 mm ID tubing; no listing prints the valve's barb size, so test the fit on your own tubing.