The NUC5i3RYB board is not available as a standalone product. Only the VPro boards are sold as standalone products.
Your best bet is to purchase a NUC5i3RYK and remove the board from the chassis -- that is, if you can find one; this is a pretty old board (5 generations old, in fact) and has already been discontinued.
Thank you for posting on the Intel® communities.
I need to inform you that due to this product being discontinued, Intel Customer Service no longer supports inquiries for it.
However, I would like to share with you our Discontinued Products website in case you have any additional concern about the product.
Please keep in mind that this thread will no longer be monitored by Intel.
Intel Technical Support Technician