How do I measure a cassette?

[Sir Neil d'Menture]

I have a rear hub which I'm told is Bontager(or Trek). 24 spoke in an unusual pattern. I'm thinking of having it built up to use in a project, but I've no idea what size cassette it takes. This will determine the shifters I need. Apart from the obvious solution of trying every cassette going is there any way of knowing?
I've tried counting the notches but I've no idea what happens at the end!!!
Pic enclosed and the length of the splines between the two arrows is 32.75mm.
Anyone know if this is 9, 10 or 11 speed?

 

[FluffyChicken]

8, 9, 10 all use the same frehub. That's not a 7 speed so it's be 8-10 speed Shimano style.

 

[Sir Neil d'Menture]

Re:

Super answer. Many thanks.

 

[FluffyChicken]

it's actually measure to the end of the freehub by the way so ~35mm

 

[Sir Neil d'Menture]

Re:

Thank you. I wasn't sure which measurement to take, but I presume that won't change the previous answer.