Tense belt of a kangoo

Hello people, someone knows how many mm of tension carries the distribution strap of a kangoo, in the manual they show how they measure it with a speech that talks about sem units that have no convert to mm. I ask how many mm because here in Argentina you get a device that is something of 270 pesos but measures the tension in mm.
If anyone knows anything, I would appreciate the data.

Hello friend if you do not have the device tensala so that when you take it between the thumb and the index in its longest section you can barely twist 9 90 degrees there you look perfect, luck and greetings.

Hello the tension of the belt either of the alternator or the distribution, or any strap when you do not have the tools and do them by hand, you have to tighten in such a way that you can move it or twist it a little less than the ninety degrees, I take as an example the belt of a pants, when twisting it remains with its inner face looking out.

Hello friends, thank you for presenting, I am going to pay attention to you, the alternator's belt never found the right tension, more than anything because of the topic of preserving the rulemans, the apparatus to tighten it I am doing by copying it from the original, I barely finished it I put the pictures and I say how to do it, it is very simple. What I am going to do is finish it, tighten the strap based on what you advised me not to exceed 90 degrees and there I will take measure with the apparatus to see how many mm they are.

The apparatus is that of the photo but it is in mm, if twisting the 90 degree strap it looks good is not worth spending so much.
being that it is so easy to do.