The DeeZee Truck Bed Mat # DZ86965 is made of 3/8 inch thick Nyracord. It's designed to hold up to being abused.
If you watch the video I've linked, around the 2:50 mark you'll see bricks dropped into the truck bed to show you how the mat is durable and protects the truck. view full answer...
The Quick Splices - Self-Stripping Connector - Closed Port - 14-16-18 Gauge - Blue - Qty 1 # SWC502905-1 is weather proof and water tight, but not waterproof. To further assist I recommend adding dielectric grease # LT37534 to further protect the splice from water and debris. As long as the grease remains as a protective layer, you won't have issues but it isn't recommended to submerge. If you are looking for a submersible connection, I recommend the Deka Heat Shrink Butt Connector -... view full answer...
You are correct that the material under the cover - the panels - of the Lomax Hard Tonneau Cover # LOM45FR are made of aluminum.
The Xceed is a fit for your 2014 Nissan Frontier with a 5 foot bed, and is a simple installation as it just clamps onto your truck's bed rails. It will do a perfect job of offering your Frontier's bed protection will also improving its aerodynamics to resist drag and improve your miles per gallon.
I have added a link below to a video review for you to check... view full answer...
I recommend taking a look at the Malone TradeSport Truck Bed Ladder Rack w/ Load Stops - Aluminum - 800 lbs # MAL55VR. This is a very affordable setup that clamps onto the bed rails of your 2018 Nissan Frontier, as long as it is crew cab 5 or 6 foot bed without utili-track system, or if it is king cab 6 foot bed without utili-track system.
T-slot channels are integrated into the crossbars of this ladder rack, making it very easy to install a wide array of accessories like kayak carriers... view full answer...