I emailed Hollis a few weeks ago to enquire why my near new Explorer 2 had the sensors from the version 1 with a jack connection rather than the prism 2 sensors with a molex connection that is supposed to be standard on the 2!
From the website:
"3 pronged gold plated oxygen sensor connectors improve oxygen cell linking and millivolt data transfer to the head assembly"

So far there has not been a response, does anyone know if this is an issue worth pursuing (where there any connection problems with the jacks)?

Apart from the above issue the rest of the unit appears to be version 2 spec!