Purchased this for large glass magnetic board. Unfortunately the magnet on the ruler is not strong enough to penetrate the glass element of the board so was rendered useless for the reason I purchased it.However I checked it against a “normal” white board and the magnetic element worked perfectly well.One key point is that the ruler comes in 3 pieces and needs to be put together. They claim this is for storage which it does help with but I feel it reduces the sturdiness of the ruler. This can impact on the ability to draw straight lines....The protruding handle is a nice feature.