Top surface size 5" x 6-1/4". Slot size 2" x 4-1/2". Rated for at least 10,000 lbs. Super heavy duty adjustable base plates for a lathe, mill, boring. Mill, surface grinder, radial arm drill press etc.
The screws have not been run in quite some time you may need to take them. Out, lube them and put them back in place.Pretty sure they are Made in the USA but I do not see the name.