Iron-on patches with embroidered overlock border. 
High-quality digitalized printing, it won't crack or fade away.
PS.: Iron-on adhesive is very strong but is not forever. 
For a stronger attachment is a good idea to sew it on after ironing it on.
 
SIZES:
Square = 10cm x 10cm
Rectangular = 10cm x 8cm
Round = 8cm