1. Stationery office rulers belong to 16 categories:
1616 office drawing instruments, painting instruments, square ruler 160069, compasses for drawing 160096, curve board 160107, drawing instruments 160125, drawing instruments Use tracing needle 160184, scale plotter (drawing instrument) 160208, drafting ruler 160234, drawing square ruler 160297, drawing square ruler 160297, painting T-square 160298, drawing T-square 160298? Scale ruler C160098
2. The hand tool T-square belongs to category 8: T-square (hand tools) 080017
3. Other rulers belong to category 9.