I see you have been building some for the Ocean Institute, so good to see you have demand, and perhaps a queue is forming :-)
I see the kits are marked as "pre-order", what is your anticipated lead times for shipping on new orders? Di you foresee a point when they become ex-stock or with a known lead time?
Obviously 3-D printing is one area you almost full control over but for components like the controllers etc are you holding stock or are you dependent on supplier availability and those being delivered to you first? Likewise RPi's, which in some areas are in short supply, and if so, and thinking forward regarding replacements can RPi 4's be used? Noting of course manufacturer production horizons, I think RPi 3's are due to still be produced for several years but in some areas I can get 4's easier than 3's.