Offered for sale is this Avantone Kick Pro sub-frequency kick drum microphone. It can do awesome things, but I've simplified my recording setup and no longer have enough inputs for this. I barely have the knowledge to EQ and mix one kick drum mic, let alone two.

Comes with the heavy-duty stand, product documentation, and drum key (I never saw any need to adjust the mesh head tension--it "thumped" right out of the box, and I'm far from a pro). 

Product description from Long & McQuade:

Give your kick sound the subsonic signature it's always wanted.
Avantone Pro is back again with a another classic from the past! Introducing Kick - a sub-frequency microphone that utilizies their famous reproduction "white cone" low-frequency driver. Kick brings the boom from your instruments out to the forefront, making large-sounding sources sound massive.

Not just any driver, but THE driver.
The Low Frequency driver is the AV10-MLF. It has a single continuous press formed cone to match that classic sound. This allows a much higher level of quality control and consistency during the manufacturing process.

Includes a heavy-duty stand.
The Kick utilizes a real wooden drum shell, and mounting it on a standard mic stand just won't do. That's why Avantone Pro included a stage-ready double braced drum stand. Whether you're in the studio or on the road, the Kick is ready to deliver!

Features
• Delivers strong bass reproduction
• AV10-MLF driver
• Real drum shell
• Includes heavy-duty stand

Specifications
Type: Moving Coil Dynamic
Frequency Response: 50Hz-2,000Hz
Output Impedance: 6.3 Ω
Pattern: Figure 8
Element: AV10-MLF 18cm cone
Connector: Male XLR
Shell: Birch Ply
Drum Head: Mesh 10"
Size: 11.375" x 11.375" x 5.5" (without stand)
Weight: 3.1kg / 6.8Lbs (without stand) / 4.6kg / 10.1 lbs (with stand)