STF Roller frames were designed exclusively by Sefar to provide the screen printer with a retensionable frame that offers improved engineering and characteristics for better screen printing performance, and are compatible with other retentionable systems available today. STF Roller Frames are available in a wide variety of lengths and widths. They are available in two different roller diameters and can be purchased in two different formats (with and without a square bar to accommodate different presses).