Review on Ultimate Woodworking Marking Tool: Center Scriber Line Scriber with Offset Marking for Precision Woodwork - Fits Standard Pencils - Blue (1) by Joshua Cameron

Accuracy: I just tested it on a 2x4, rode it with posts on both sides, and it drew a line in the exact same spot, which tells me it marks exactly that Center. I also used an edge cutter to mark every 1/16" to 1/2" line on the edge of my bench and lined them all up with my tape measure. If I need something more precise, I still don't use a pencil. Ease of use: I see some people having trouble with pens that don't fit. I've tried both a round pencil and a hexagonal pencil and they both fit. My old plastic Bic mechanical pencil didn't fit, but I'll use a pencil holder and leave a wooden pencil in it. It couldn't be easier to mark the middle. At first I didn't bother with the edges, but they're pretty smooth too. Price: This looks exactly as it is being sold by a popular online woodworking retailer for 1/4 the price. The plastic is good and strong, the magnet holds well. Summary: Stop measuring, drawing diagonals, or eye marking the center line on the board. This thing couldn't be easier to use. Stick a pencil in it, make a mark and hang it back. The magnet is strong enough to screw everything to the screw on the side of my bench. Can't beat the price.