Some believed it was not really possible or feasible, BUT:
Bel has recently announced a new high-end model called the STI Driver. A recent SpeedZones field test found the STI Driver to be completely undetectable by all currrent RDDs such as the SPECTRE III! The STI Driver model has been in the offing for some time and appears to be nothing short of an engineering "miracle!" Kudos to Beltronics for their innovation!
From what we gather it is built like a tank and performs exceptionally well with all radar bands and has undergone a major improvement to off-axis laser detection capabilities.
We are anxious to get this new model into our test cycle.
Valentine Research has recently informed me of an updated model now shipping (ver 3.826) which has some improvements to their "J" function (muting out false Ka LO leakage from lesser radar detectors in close proximity). After the Christmas and New Year's holiday, we will send out our Valentine One (ver 3.826) to get flashed.