D669 Micro-computer Racquetball training machine Design concept : Racquetball called America racquetball, is derived from a ball game played against the wall .This movement quickly fascinate, and developed into today's Racquetball, Functional training
Elbows in any degree As we known in the pipe fitting and elbow standard,the butt welding elbows commonly are 45°,90°,180°. But in the projects,sometimes the engineer or designer may use the elbows which degree are not the standard degree,such as 60°,70°or