Bestop PowerBoard Retractable Electric Running Boards 75146-15 Extends down automatically when door opens , retracts up when door closes;6.25 inch extra wide step ;Sturdy, cast aluminum alloy arms allow step to descend up to six inches; All PowerBoards feature an integrated light kit; Each PowerBoard can hold up to 600lb load capacity PER SIDE and have been climate and salt spray tested to operate in any climate; 3 year/36,000 mile limited warranty; Extension arm is available to provide an additional 2 inches of height for lifted trucks CHEVROLET GMC SIERRA 2500 HD SIERRA 3500 HD SILVERADO 2500 HD SILVERADO 3500 HD BASE DENALI HIGH COUNTRY LT LTZ SLE SLT WT 2011 2012 2013 2014 2015 2016 6.6L Duramax Turbo Diesel LGH (400) 6.6L Duramax Turbo Diesel LGH (403) 6.6L Duramax Turbo Diesel LML (400) 6.6L Duramax Turbo Diesel LML (403) DIESEL Bestop Bestop PowerBoard Automatic Running Boards (Black) - 75146-15 75146-15 Power Running Board