Extang tonneau covers are used to cover the bed of a pickup truck and allegedly streamline the truck bed and improve fuel economy. Scientific studies have proved the difference to be negligible, however, because with the tailgate of the truck in the locked position, the truck bed creates a vortex that air passes over at speed.
Depending on which cover one buys, the Extang Tonneau covers support many different trucks. For instance, the classic Tonneau cover supports many Ford, Nissan, and GMC trucks while the Solid Fold cover supports the Honda Ridgeline and a few Dodge trucks.
The different Ford F150 Tonneau covers available in the US include: Seal and Peel, Hard Shell, Roll Up, Lund Snap, Sure Fit, Extang, Hinged and Tri Fold.
Here's a site that sells a variety of different tonneau covers by mail order: http://www.truckchamp.com/tonneau-covers
Soft Tonneau covers range from approximately $300 - $500. Hard Tonneau covers are double the price, ranging from $600 - $1000! There are other varieties, but these are the two most popular.
New Tonneau Covers sell from $164.95 plus shipping.
Tonneau covers are used to cover the open truck bed of a pick up truck. These types of covers are cheaper than caps and are available in multiple configurations. Tonneau covers are good for concealing sensitive materials with a slim profile, unlike a cap. Suppose you're carrying dry ice, you wouldn't want to asphyxiate because the back window was open, with a Tonneau your window is left unobstructed.
That is a tough one. I checked the application guides for Advantage, AgriCover (Access), BAK, Extang, Lund, Pace-Edwards and Truxedo. None of these producers made a model for the 2002-2006 Chevrolet Avalanche. Sorry.
Hard tonneau covers are made out of thermoplastics. Soft Tonneau covers are made out of weather resistant fabrics of various types, most usually coated with PVC or made out of Vinyl.
When shopping for tonneau covers you should always shop for materials that are durable and stain proof. You should always compare price online.
You can find truck tonneau covers at Auto Anything online at (http://www.autoanything.com/tonneau-covers/10A50174.aspx). They have covers that fit all sizes of beds and you will want to order the one that is specifically for your make and model of truck for the best fit. Another site to check out is TruckChamp.com at http://www.truckchamp.com/tonneau-covers.
It has been estimated that 400,000 tonneau covers were sold in their peak year. With truck sales down, there are less sold each year.
These covers are not free however some sites do provide free shipping when purchasing tonneau covers. Most of the nice covers cost between 200 and 400 dollars.