Here are several of the most popular options for sealing tonneau covers into the truck bed:
Snap. This type has been the sole option for quite a time. Many of the early soft tonneau covers came with either buttons or snaps in order for it to be securely attached into the truck bed. If you plan to purchase such with buttons or snaps, remember that you should buy one with snaps that are adjustable. Depending on the weather conditions, the cover may shrink or stretch up to an inch, which necessitates adjustment on the location of snaps or buttons.
Snapless. Many of the latest designs of bed covers already feature a sealing system that is snapless. This is a great sealing option to use on covers for the whole year, whatever weather condition it would be used in. What eliminates the snap is the use of a seal called tongue-and-groove that is rubbery or plastic in texture. The plastic/rubber seam will simply be pushed into the aluminum channel. It will then slide into the hand down to the truck bed rails. Such is the easiest sealing option.
Velcro or Hook & Loop. If the tonneau covers you decide on include a Velcro-type of sealing system, this would ensure easier and faster opening and closing system. There will be no need for grooves, channels or even special snaps making it have a low-profile look. This kind of seal if very ideal whatever weather condition because it is really weatherproof.
Remember that it is important to check out the versatility of a truck bed cover, as well as the security it will provide. A hard cover is very reliable in terms of securing your truck bed. The smooth fiberglass bed coverlid by Gaylord, the very strong but lightweight composite bed cover by Armor Lid and the canister-style aluminum tonneau by Pace Edwards are great options in order to ensure protection of your cargo. They are manufactured using dependable materials with built-in locks in order to keep your truck bed cargo safe. However, even if they provide great security as well as cleaner look, they can pose quite a challenge when opening and removing to haul cargo that are oversized.
For oversized cargo, you might want to consider the roll-up style by Pace Edwards - a hard cover that can be operated as a roll-type desk. It can slide forward and roll to become a storage canister in the front part of your truck bed.
For additional protection and total security of your truck bed, get a tailgate handle lock since this would prevent prying people to open your truck tailgate regardless of which type of cover you install.