Our presale of the WS Flash Masta cartridge for the WonderSwan has started. We have stock to assemble and ship 50 cartridge boards. That’s what we are listing today. Once they are sold, we will assemble and ship them out. I would expect to have them all shipped out by mid December.
Please read the product page at https://www.flashmasta.com/product/ws-flash-masta-usb-cartridge-for-wonderswan/ to educate yourself about this product.