This is a great product that has been around for as long as I can remember. When bolts or screws on a car or anything else for that matter will not budge or other such challenges it is very instrumental in penetrating the areas by spraying it in there and hence making it easier to get out the stubborn screw or bolt that needs to come out to do the repair.
I have kept this on hand at my house for many many years. Recently I needed to buy some more of this product and was pleasantly surprised at the way it comes with a handy new smart straw that it attached to it. You can no longer lose the straw because it is attached in a very hand fashion. I like that. It has a hinge where you can raise and lower the straw. You can't beat that.
Obviously this item can be used to lube many things. I have a project that I am working on this weekend. A couple of small bolts are holding on a part on my vehicle that I want to replace. They are very stubborn and holding in there tight. Yesterday I sprayed the area where those bolts are with this product. This allows it to penetrate the area over night. It should make todays job pretty easy now to take those bolts out and finish up. WD-40 is a great product and should be kept on hand in every household.