I switched this out of my Mesa Boogie Studio 22 plus amp. It was a stock Boogie speaker back in the day, rebranded as a Black Shadow VS12. It works and sounds great, I just needed the lighter Neo Creamback Speaker.

From the internet:

There is no "Black Shadow model" - it's the brand name Mesa use for all their OEM speakers.
Mesa Boogie Vintage Black Shadow VS-12 is a rare 12-inch, 50-watt, 8-ohm guitar speaker custom-built for Mesa Boogie by Eminence during the 1980s.

• Manufacturer: Eminence (custom-made for Mesa Boogie). 
• Power Handling: 50 Watts. 
• Impedance: 8 Ohms. 
• Size: 12 inches. 
• Era: Early to mid-1980s, often found in metal-grill, half-back Mesa cabinets or vintage combos.
• Sound Profile: Known for a warm, ceramic-magnet response with prominent mids, sometimes compared in style to a vintage Celestion or a modern Eminence Tonker.