Commercial door parts and hardware are available in different grades.
Grade 1 is Best, heavy duty, commercial grade usage
Grade 2, Medium & light duty, commercial usage
Grade 3, Economy, light duty, residential
The quality of the product is a reflection of the grade level. Grade 1 hardware will last longer than grade 3.
When selecting door closers and lock sets, consider how long you want them to last before you have to replace again.