Compatible with Casio MDV106 Bands, 22mm Quick Release Sports Silicone Band Strap Replacement Wristband Compatible with Casio MDV106-1AV / MTP-VD01 Watch

I think what you are referring to is “notching.” If you want a rubber strap for your Duro without much fuss, this might work for you: https://a.co/d/0gWKkjTU