This is where I bought mine, looks like it's still available.
Try the coupon code, MANTIC59, to get 20 more blades.
Parker Adjustable Injector Razor with 20 Blades - https://www.supersafetyrazors.com/parker-adjustable-injector-razor-with-20-blades/
Looks like it is sold out at Super Safety Razors: there is no "add to cart" option (just "add to wish list").