"Each PACK includes 2-brackets that make 1-saw horse." 1- ONE Is english not your first language?
I have found through the years the online site does have different "numbers" than the store itself. Sometimes a different supplier etc... As far as the warranty its no big deal for as cheap as they are. If they are going to break/fail etc the lumber will probably fail causing the bracket to twist etc.. Also I prefer my sawhorses a few inches higher than these. Bottom line if you want to carry a seldom used set of sawhorses these will do the job as long as the ground is level. I have probably built 100's of sawhorses on job sites with NO brackets at all.. Cheap and can be trashed easily. Personally I have used Stanley sawhorses for my personal use for a long time. They adjust height and width. They weigh a few pounds each and take up little room in my truck. Costly if you seldom use them about 60-65 dollars BUT handle more weight and should last forever.. Model # STST60626 Internet #203799620
1 pair for 1 saw horse
I used a 2" galvanized nail. About 1/8" diameter.
You could drill a hole through the horizontal 2x4, put a long screw with nut and make them pretty easy to fold. Or if not moving around a lot just don't use a fastener in the horizontal piece.