SPI Height Gage Scriber & Clamp Accessory Kit Scriber Post dimensions... 8.8mm wide 9mm tall Clamp inside dimensions... 10mm wide 24mm tall Designed for use with the following SPI Height Gages... SPI 12" Double Beam Height Gage SPI 18" Double Beam Height Gage SPI 24" Double Beam Height Gage Accessory Kit includes... Scriber Clamp Indicator Holding Bar