The HD and Sears Magnavox lcd tvs, model 42MF531D are not the same. The HD is model "/37" and the Sears is model "/37a."
The HD model has a contrast ratio of 1200:1.
The Sears model has a contrast ratio of 3000:1. (Supposedly, anything above 2000:1 is superb.)
It took me a long time to find this out and finally did by calling Magnavox.
See the "Leaflet" files for the two 42MF531Ds at:
usasupport.magnavox.c0m (change the 0 to an o in com)