1- Click on the link below:
https://mysmartcocoon.com/products/single-4x10-smart-booster-fan?variant=37444683432133
2- make sure your cart is empty. If it is not, please click on it and remove the existing items.
3- Click on the arrow to open the available sizes and choose 3"X10"
4- Go to your cart and ensure you have the correct size. Also, could you please change the quantity here?
5- click on check out and proceed with payment.