What is the difference between these two models?

Hello, I’d like to buy a complete A168 kit, but I’m not quite sure what the difference is between models #28 and #20. Could you explain the difference to me?

​

https://skxmod.com/products/28-casio-a168-f-105w-completed-build

​

https://skxmod.com/products/20-casio-a168-f-105w-completed-build

​