Flange Wizard® On/Off Magnetic Blocks for Burning Guides On/Off magnetic support blocks can be attached to any standard square or straight edge, up to 1/8 inch thick, to form your own burning guides. Blocks are machined from aluminum and have grooves on three sides. Included are set screws to easily adjust blocks on straight edges or squares. Options available for one On/Off magnetic block (MSB201) or two On/Off magnetic blocks (MSB202). Pack of 2.