Module / Part Number for 4xSFP+ Module for XGS2300 appliance?

I am working with a client that has two XGS2300 appliances in their network.  They did not realize they need SFP+ instead of SFP, and asked me to help them acquire the proper module to install into the XGS2300 for the 4 x SFP+ module.

I'm aware the module exists, but I cannot find any part number or purchase mechanism to obtain the module.

Does anyone have details on the module itself that I can get ordered through vendors for my client (via ESafe, their vendor that handles the Sophos stuff), so that I can make sure we get the proper device?