Swivel type pintel bolt size?

[linx310]

I purchased a NOS swivel type pintel to install on my M1009 since it has the older style mount for the pintel with the giant bolt on the end.

Do they have a special tool or wrench for this giant bolt or do I just use a monkey wrench?

 

[linx310]

Here are some pics of the bolt i am talking about. I have circled it in red.