Hi,
After some searching on the internet I have found out that the wire tensioner I have been trying to find out who makes it is used in some Hangar 9 ARF's. But I can not find it as spare part at Hangar 9.
I will dig some more with help of Google.
/Bo

Here is the link your looking for
https://hobbyking.com/en_us/pull-pull-3mm-clevise-quick-link-couplers-26mm-length.html
https://hobbyking.com/en_us/pull-pull-2mm-clevise-quick-link-couplers-20mm-length.html