The Westin PRO TRAXX Oval Nerf Bars - 4" - Black Powder Coated Steel # 21-22775 and Westin Platinum Series Oval Nerf Bars - 4" - Black Powder Coated Steel # 21-2775 are very similar and both fit your 2018 Toyota Tacoma Double Cab. As you can see in the attached photo, the Pro Traxx has a slight curve at the end of the bars, while the Platinum Series has a more pronounced curve at the end. Also, the Pro Traxx has a more rigid and bumpy step pad and the Platinum Series has a somewhat smoother... view full answer...