Tube condenser mic with 3-way switchable pattern (cardioid, omni, figure 8), based on the old Telefunken ELA M 251- apparently more affordable than the vintage Telefunken at "only" $5000. Currently released by Bock Audio, founded by vintage mic expert David Bock, who was part of Soundelux until 2006.
[product page (Bock)]
Mentioned in a MIX Magazine article on 2011/08/01:
Billy had just acquired an amazing vintage Martin that we miked with a Soundelux e251, and an AKG 451 and 414. These were all amped with a modified Neotek sidecar and summed on a Neve 5088 mixing board using the Roy Thomas Baker summing method.