The 40mm x 40mm upright extrusion is the basic pole profile for the shell scheme booth, widely used in standard exhibition booth around the world. In some Asian countries, they call it as 8K post, in some European countries, they call it as R8 system pole. Never mind what they call, with 8 system grooves, and the groove width is 4.3mm, it enables the tension lock to get in and fix firmly, to make the 3 x 3 x 2.5 m standard booth. By adopting the German standard, the quality is well accepted by European and USA customers.