You need either a top or bottom mount for the tubemeter.
They are 1/8 thread so you also need the thread adapter to 1/4 which is also on their site. (depends if your using aqua computer res or not I think their res is fitted with 1/8 mount but check on the website.) just checked their website, aqua tube 1.1 has bottom mount 1/8 mounts if your using their res.
I am drilling and tapping my own 1/8 hole in the bottom of each res as I don't have enough space between the res and top of the case with the USB/aquabus cable attached to use the standard 1/4 fill ports on my res.
Ok....I understand .

Many thanks Phatboy69