AEA TERMINATOR PRESSURE GAUGE THREAD SIZE?

My Terminator gauge took a dump and I don't know the thread size. 20 miles to the hardware store, so hope to save time and gas. Texts to a few dealers have yielded zip. Two 1/8 npt gauges that are about an 1/8" different in thread diameter dont fit. It might be metric? M6 too small, maybe m7? If you KNOW the ANSWER, please respond. Thanks, Bill.
the thread size is an m8x1.00 but the only person i found that has the gauge with that thread size is an aea product but you can get a gauge off of amazon with the 1/8 threads and get an adapter