Tunnel hight?

I was reading the Arena manual and it said that the tunnel height was 18 inches tall, but the field drawings said that the tunnel was 16 1/2 inches tall. Does anyone know what the actual hight of the tunnel is?

Sorry for the misspelling of height*.

Perhaps these threads might help you. I found them in less than 2 minutes searching.

http://www.chiefdelphi.com/forums/showthread.php?t=79904&highlight=tunnel+height

http://www.chiefdelphi.com/forums/showthread.php?t=80346&highlight=tunnel+height

http://www.chiefdelphi.com/forums/showthread.php?t=80669&highlight=tunnel+height

http://www.chiefdelphi.com/forums/showthread.php?t=79960&highlight=tunnel+height