Had a issue with my Mishimoto coolant tank leaking at the sight tube. I shot them a email asking if they could provide me with the thread measurement for the holes in the tank, was gonna plug them and delete the leaking sight tube assy. Less than an hour later, I got a email back with exactly what I asked for. Outstanding customer service. For those wondering, the measurement you need to plug the holes is 1/8 -27NPT.