Anyone who spends time around power saws, routers, and other tools that spin sharp edges at furious speeds has a healthy respect for their danger. A good rule, one I learned before my teenage years, is never let your fingers get within an hand’s width of a cutting edge. If my digits might get too close, I need a push block or stick. I’ve always used scrap wood in the past, but now I have a Kreg Multi-Purpose Push Stick.
Kreg molds their product from impact-resistant plastic in the company's standard blue color. The “stick” is about 8” long, 4” high and half an inch thick. At the bottom edge, there’s a quarter-inch lip to hold the workpiece in place. At the top, a fist-shaped hole with ergonomic plastic cushion provides a secure grip. To make their push stick multi-purpose, Kreg puts a groove in the handle for a pencil and builds in a sliding metal rule (marked in 32nds of an inch on one side and millimeters on the other) for use as a depth gauge, etc. The push stick also has a built-in magnet so you can store it on the side of a table saw or other steel surface; if the saw housing is non-magnetic Kreg supplies a small steel rectangle of steel with double-sided tape that you can mount wherever it's needed.
Whether shop-built or store-bought, a push stick should be standard safety equipment in every woodworker’s shop. Since this design rides atop the stock, fingers are kept safely away from saw blades and router bits. Some users might find the quarter-inch lip a bit too low-profile, but it’s worked so far for me. I do find that the steel rule is difficult to move; but it’s improved with use. Except for that, I’ve been satisfied with the Kreg Multi-Purpose Push Stick. It may cost more than scrap wood, but it’s also more versatile.