National standard 0.5 is good.
The quality, content, performance, safety factor, etc. of non-standard products are lower than those of national standards or cannot meet the requirements. Special materials or process structures may cause safety hazards. Non-standard products refer to products or equipment that are not manufactured in accordance with the unified industry standards and specifications promulgated by the state, but are designed and manufactured by themselves according to their own use needs and whose appearance or performance are not in the national equipment product catalog.
National standard products are produced in strict accordance with national standards. Even if there are errors, they are within the allowable range. National standard products have stricter material selection and process requirements, so their quality is much higher than non-standard products.