This is my favorite tool.  The reciprocating tool is not used to build stuff, it is used to tear down or destroy things.  Its a fun tool, well actually they are all fun, but I love this one.  A reciprocating saw is probably not going to be at the top of a list for tools most often needed, but when you need to destroy anything, it is the most handy tool in the world.  Milwaukee is the king of the reciprocating saw, the Sawzall.

A reciprocating saw is a simple tool that has a motor that drives a blade back and forth.  There are two main power types of saws, a corded and cordless saw.

A cordless reciprocating saw is nice for quick jobs such as cutting a pipe under the kitchen sink, but if you are doing some serious cutting, be prepared to have a lot of batteries by your side.  A cordless also lacks true cutting power.
A corded reciprocating saw will just about cut through anything you want and if you have the right machine, it won’t bog down either.  If your looking to buy a reciprocating saw, I would buy a corded one.  Most cordless kits now come with a reciprocating saw.
Reciprocating Saw Feature
Cord – If you buy a corded version, make sure you get one that has a detachable cord.  Since this tool is for destroying, most of the time you will have debris on the ground and you will be bound to cut the cord.  A detachable cord is very easy to replace.

Orbital Action – Orbital action refers to the blade movement.  A typical reciprocating saw moves back and forth, while an orbital saw not only moves back and forth, but it also moves up and down.  Orbital action will help cut through material, except for pipe, a lot faster and easier.  Make sure the tool has an adjustment that allows you to change the setting from orbital to a straight cut.

Reciprocating Saw Blades

There are two types of blades for a reciprocating saw. Metal and Wood Blades.  Metal blades have more short teeth closer together and are used to cut through pipe and other metals.  The wood blades have longer teeth that are spread farther apart and are used for cutting wood.  Most of the time you will use a bi-metal blade.  This is used for demolition, such as wood and metal.  A perfect example would be cutting through a window frame.  Most of it will be wood, but you will probably hit some nails or screws.