I'm looking for the dimensions of the chain tensioner Fortschritt e931.

Hello.
The owner of the tractor lost the plastic piece during operation. This is the part no. 35 in the picture.
[Blocked Image: http://fs1.directupload.net/images/150623/temp/222wtf5k.jpg]
Someone knows the dimensions of this item? I want to make it yourself.
Best regards.