Air China 21,29,51,62

China

21,29:

• paper  
• open gussets               
• tear off strip   
• peel off sticky strip in front
  
• straigh cut

          21: no tear off line on back

51:

• paper  
• open gussets               
• tear off strip   
• peel off sticky strip in front
  
• straigh cut
• manufacturer in the left gusset:

62:

• paper  
• open gussets               
• tear off strip   
• peel off sticky strip in front
  
• straigh cut
• manufacturer in the left gusset: