For the largest possible performance gain replace the entire air box and intake tract with the aFe Stage 2 Open Element Air Intake System. 
 Features
 - No Floating Tubes  Built-in ram scoop forces cold air to filter for greater efficiency and performance gains.
- Clamp Stops  Raised stops on aFe tubes provide a more secure seal and eliminate slippage versus flat, straight tubes.
- 3-Angle Adapter  Specially developed velocity stack with 3 different angles dramatically increase airflow from the filter to the intake tube.
- Quality Hardware  aFe uses only top-quality hardware like stainless steel button head bolts and brass inserts.
- 3 Filter Media Choices  Choose from the Pro 5R, Pro Dry S or Pro-GUARD 7 Filter.
Application:
- 2011-2015 GMC SIERRA 2500 HD V8 6.6 
- 2011-2015 GMC SIERRA 3500 HD V8 6.6 
- 2012-2012 GMC SIERRA 3500 HD DENALI V8 6.6 
- 2012-2012 GMC SIERRA 3500 HD SLE V8 6.6 
- 2012-2012 GMC SIERRA 3500 HD SLT V8 6.6 
- 2012-2012 GMC SIERRA 3500 HD WT V8 6.6