101 Tech USA have the PolarStar Kythera available for pre-order:
The Kythera has been the most eagerly anticipated product from PolarStar in the past decade. This HPA system is a radical departure from all previous systems that PolarStar has produced since the Kythera does not use a battery, an FCU or any type of electronics. The Kythera is completely mechanical. This means you never have to worry about charging batteries or work with delicate electronics. It also means that the system is completely waterproof.
The name "Kythera" (ky-the-ra) was derived from the Antikythera Mechanism which is a mysterious device that was discovered by sponge divers off the coast of the Greek island Antikyther. The mechanism was so advanced in design that scientists have been studying it for decades to discover its purpose. The machine dates from around the end of the 2nd century B.C. and is the most sophisticated mechanism known from the ancient world. Nothing as complex is known for the next thousand years. The Antikythera Mechanism is now understood to be dedicated to astronomical phenomena and operates as a complex mechanical "computer" which tracks the cycles of the Solar System.For this reason, we used the name Kythera for the valve mechanism at the core of a new line of PolarStar mechanical HPA systems. Although it contains very few parts and is easy to install and maintain, the system incorporates a very intelligent design and is unlike anything else on the market. The system was designed as a mechanical system from the ground up and uses a realistic trigger mechanism which can be applied to single-shot, semi-automatic and fully-automatic systems.
Available April 2020
The Kythera (KIH-THEER-A / KIH-THER-A) system is designed to replicate the function, weight, and feel of a real single-action firearm trigger. The trigger is also adjustable, allowing the user to fine-tune the weight and over travel.
The Kythera operates without the need for air to control the opening or closing of the valve. The efficiency and consistency of the valve design allow the mechanism to release the valve at the same point with the same force applied, regardless of the trigger input.
The steel cord visible at the back of the system is attached to a cocking mechanism for the internal spool valve. Although the system automatically cocks the spool valve when the system is pressurized, since the Kythera uses a balanced valve, it is possible in certain situations that the valve could stall and needs to be manually cocked. This typically only happens if the system is run completely out of air so that the pressure drops below the operating range of the system. The cord is designed to be either routed through the grip of the rifle for easy access or even possibly attached in some fashion to the charging handle.
