Groove-less frames and accessories are a general category for aluminum extrusions that are flat on all 4 sides and their dedicated accessories. A feature of this type is that the absence of a groove prevents the accumulation of dust or dirt for excellent hygiene management. The fastening parts for connection have also been designed to enable mounting with no unevenness. The aluminum extrusion of the groove-less frames and accessories are available in 2 types, square or rectangular. A type with a groove on 1 surface is also available for mounting accessories. These are often used as cases for equipment in food-related factories or locations where a clean environment is required.