In my opinion almost every skier should be using a Svenfit ski boot liner, this liner is called Zipfit in the USA.
The liner was developed by a guy who once claimed to be an Aussie, born and living in Sydney called Sven Coomer.
The Svenfit liner will change shape daily to adjust the fit to whatever ski sock you are wearing on the day, it adapt to most new shells if required for the same boot size and rough shape, the filling material can be added or removed as required throughout the long life of the liner, which is usually more than the life of many boot shells through the years, almost every good skier I know is using this boot liner.
Here is a copy and paste from Svens own website on his liner.
The Zipfit© and OneMinuteFit© man is (Sydney born) Sven Coomer. He developed and perfected the recent application of “OMFit” molding compound. After 25 years of competing and coaching in 7 sports through Olympic level, and studying engineering and industrial design, Sven began designing and developing ski boots with Nordica in 1970. That was in the transition from leather to plastic boots. His contributions there laid the foundations for the state of the art in today’s ski boots. In 1978 he opened a ski boot fitting and orthotics development shop at Mammoth Mountain, California, from which came more famous boot models, boot fitting schools and Superfeet. In ’88 he began Zipfit to develop the missing links, the orthotics and inner boots.
OMFit is a proprietary formula of granulated cork and dry-ceramic “clay” binders. These combine to create the optimum viscosity and density to work in the extreme and most demanding environment of ski boots. The OMFit is perfected to perform within his other unique Dynamic Molding System. This enables the OMFit to adapt and work with you, allowing your anatomy to settle into the optimum and most efficient relationship and effective support within your ski boots. This changes constantly whether you are skiing straight or carving high speed or slow speed turns. It is not a casting of one passive position, as with foam or silicone injected liners. Sven was also accountable for developing the best ever foam liners and patented silicone liners.
Dozens of formulas were tried in evolving this one functional recipe that works; responding perfectly with your anatomy dynamics and body heat within the complex demands and environments encountered in skiing. Cork is superior because it never compresses, deteriorates or shrivels-up the way all of the synthetic materials, foams and fillers did in extended testing. Cork yields under pressure and vibration without deforming or losing support and always returns to original memory. OMFit is also organic, the best insulation and the most ergonomic feeling around your anatomy. In addition, it lasts for at least 600-700 days of hard skiing. The paste is proven to promise you the best fitting, warmest, most comfortable, supportive and best performing ski boots you could ever imagine.
I was only reading last week that Steven Lee uses them and swears by them as the best liner he has used.
My online store usually has all sizes in stock.