Most of the engineering has long been done; it is the productization (i.e. turning the device into a consumer product) that has taken–and continues to take–a long time. (In fact, it was an obstacle since the outset 😉 !)
The enclosure is being selected, and will subsequently be tested. Once that succeeds, enough interest has to be shown in the product before a large number of units can be created for sale.
