12 mil (300 microns) thick. Size 8.5 x 11" (216 x 279.5mm).  For laser printers -  will also work with offset presses and Epson Stylus inkjet printers with Durabrite Ink (C82, C83, C85, C87, R200, R800....).
However, if you have an inkjet printer, best image quality is achieved by the Inkjet Teslin. Price per box with 100 Teslin sheets.