2.5 to 3.5 - 12v trigger?

[holsen]

Trying to set up a trigger from the WiiM Pro to my Amplifier. The problem is the Pro has a 2.5mm trigger out and virtually everything else has a 3.5mm trigger in. I can't find a 2.5mm mono cable anywhere and I haven't been able to find a 3.5F to 2.5M adapter

Has anyone been able to work this out that can direct me to a solution?
Why on earth would WiiM choose a 2.5 output?

 

[harkpabst]

As you posted this in a thread about 2.5mm - 3.5mm cables, my suggestion and that of @Burnside will not be suitable if you are using an Ultra, and a Vibelink. You will need a 3.5mm - 3.5mm cable instead.

A very good reason to rather start a new thread, too.