[Momotaro]

Since it has been asked on the forum several times, here are the Eheim metric tubing conversions:

Eheim Metric Tubing Conversion
9/12mm = 3/8"
12/16mm = 1/2"
16/22mm = 5/8"
25/34mm = 1"

 

[150EH]

That ID or inside diameter!

 

[HolyAngel]

the first number in mm is the inside, the second is the outer and the converted tubing size is Outer diameter. the inside should be the same but we dont have those fractions

 

[150EH]

Since it has been asked on the forum several times, here are the Eheim metric tubing conversions:

Eheim Metric Tubing Conversion
9/12mm = 3/8"
12/16mm = 1/2"
16/22mm = 5/8"
25/34mm = 1"

The coverted number is SAE (Standard American English) and is what you might see on a wrench or socket as a unit of measurement

3/8 - 1/2 - 5/8 - 1" are all the inside measurements of the tubing 12mm = 1/2" roughly.

The metric number that Eheim uses are ID first (ie 9/12) and OD is second. In English or SAE this would be 3/8 ID 1/2 OD

ID = inside diameter
OD = outside diameter

Sorry to be so thorough but I wanted no confusion.

 

[HolyAngel]

the first number in mm is the inside, the second is the outer and the converted tubing size is inner diameter

Edit: fixed! Thanks 150EH