May I ask what the sample parts in the picture are for? The material is made of precision steel tube

Small diameter precision seamless steel tube 28×7.5

And standard gear

Small diameter precision steel tube is a small diameter seamless tube with high dimensional accuracy and good surface finish used in mechanical structure and hydraulic equipment. Selection of precision seamless tubes for the manufacture of mechanical structures or hydraulic equipment, etc., can greatly? Save machining hours, improve material utilization, while helping to improve product quality.