heymccall, that's the Sierra VYU.
Denali says similar (but not exactly the same):
VYU Snow Plow Prep Package, includes power feed for backup and roof emergency light, (KW5) 220-amp alternator with gas or diesel engine, forward lamp wiring harness, (TRW) provision for cab roof mounted lamp/beacon, (NZZ) underbody shields and Heavy-Duty front-springs
1 - Only available on 4WD models. Not available with (CF5) power sunroof. When (VYU) is ordered (UG1) Universal Home Remote and (A48) power sliding rear window is deleted. Upgradeable to (KHB) dual, 150 amps and 220 amps each alternators with (L5P) Duramax 6.6L Turbo Diesel V8 engine.
EDIT: note 1 applies to both 2500 and 3500 Denali VYU pkg
2018 L5P Sierra 4x4 SB Denali
Sold 2011 LML Sierra 4x4 CCSB SLT
Sold 2010 LMM Sierra 4x4 CCSB SLT
Sold 2004.5 LLY Sierra 4x4 ECLB SLE
Last edited by redwngr; 01-27-2017 at 10:08 PM.