I think it's a Snap-On. I'll need to dig it out of storage, as I haven't used it in a while. It looks identical to the one that's on Ebay. Air power helps out a lot, when someone is doing production work and maybe working on several cylinder heads a day. For a hobbyist, one of the lever action types would be adequate.
Do a quick copy/paste, before the link gets zapped:
https://www.ebay.com/itm/VINTAGE-CLARK-FEATHER-CF-700-PNEUMATIC-VALVE-SPRING-COMPRESSOR/153858128496?hash=item23d2a8ba70:g:UsAAAOSwxdVeZB6H
Jerry