In one sentence, describe what the following article is about:

Carbon steel blades are the standard material used in a jigsaw. If your project requires you to cut through wood, PVC, or laminate, find a hardened carbon steel blade. Most blades will be labeled with the type of material they can be used on. Look on the packaging or on the label printed directly on the blade. Since metal is a harder material, you need a tougher blade to cut through it. Bi-metal blades have hardened steel teeth to make the cut and a softer, flexible body so they don't break. Find a blade or set of blades meant for metal cutting. Fine-toothed blades have more teeth on the blade per 1 inch (2.5cm). Fine-toothed blades are standard for cutting metal or making a clean edge on wood. Wood blades tend to have as many as 12 teeth per 1in (2.5cm), while metal blades can have up to 36 teeth per 1in (2.5cm). Fine-toothed blades work best when they're used at a slower speed so they don't break. Coarse-toothed blades have fewer teeth per 1 inch (2.5cm) and are mostly used to cut wood. If you need to make cuts quickly for a project, opt for a coarse-toothed blade to finish faster. Coarse-toothed blades leave a rough surface and will chip wood. A T-connection blade has 2 notches near the top of the blade on each side. Feed the blade through the bottom shoe, the flat guard on the bottom of the saw, until the end fits into the quick release. Make sure the blade's teeth are facing towards the front of the saw. Push the blade into the quick release until it clicks into place. The type of connection you need depends on the model of your jigsaw. Check your jigsaw's manual to see what type of connection you need. Some quick releases have a small lever you need to turn before the blade locks in. Try pulling on the blade once you insert it to make sure it fits tight. To remove the T-connection blade, pull on the lever on the quick release and pull the blade out. Make sure your jigsaw is unplugged or disconnected from power before you change the blades. U-connection blades have a single notch on top. Put the U-connection blade through the shoe of the jigsaw and hold it in place in the release. Tighten the screw that holds the blade in place with an Allen wrench or screwdriver until it doesn't wiggle anymore. To remove the blade, simply turn the screw counterclockwise and pull the blade out.

Summary:
Choose a carbon steel blade to cut through wood and PVC. Use a bi-metal blade to cut through thin metals. Pick a fine-toothed blade for making clean and accurate cuts. Use a coarse blade to cut through wood faster. Push a T-connection blade directly into the quick release to snap it in place. Screw in a U-connection blade using an Allen wrench or a screwdriver.