Adapter 60

[Heterop]

Hi,
On Zeiss page I found several options to connect camera to my microscope. https://www.micro-shop.zeiss.com/en/us/shop/cameraAssistant/step2?cType=dsc&pId=p101&cId=c1058&mcId=m1060&mcName=Stemi_2000_C.
The first option use Adapter 60 (30mm to 30mm) with Camera Adapter and the third option use only Camera Adapter without Adapter 60.
Does anyone know what the difference between those too option? If Adapter 60 is optional configuration what is its purpose?

Thanks