I bought this to trace the intricate molding around the foot of my coat so I could cut the tile to the right shape. The lock didn't work, fell off the mantle, it lost all shape. If I had been very careful not to knock it over I could have lined it up on the tile, but as soon as I tried to draw a line the pins moved with the slightest pressure of the pencil. Not worth the money. I'll probably give it to a kid to use as a toy or something.