OnMouseDown() without Collider?

Hello friends!
I'm trying to select my shooting tower by OnMouseDown function. It works fine.
But I have a sphere collider of that tower much more than itself because I am using a OnTriggerEnter function to detect whether enemies have entered my circle to start fire.
So OnMouseDown function doesn't work the way I want.

Is there any way to solve that? Or is there any function that I can use to select my tower without using a Collider?

Thanks in advance!

 

Solve that with Physics.OverlapSphere function!
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