Tech bindings - also called pin bindings or, more formally, AT bindings (alpine touring) - are the minimalist binding system that has become the standard for serious ski-touring. Two small metal pins on the front of the binding clamp into sockets moulded into the toe of the touring boot; the heel sits on a separate piece that locks down for the descent and opens up for the climb. The system was invented by the Italian engineer Fritz Barthel in the early 1980s under the brand name Dynafit and is now manufactured by every serious ski-touring brand.
What tech bindings do that traditional alpine bindings cannot: they pivot freely at the toe on the climb, which allows a natural walking stride with the heel rising independently of the ski. They also weigh roughly half what an alpine frame binding weighs - a real difference over a long ascent. The compromise is on the descent: the release mechanism is less forgiving than a modern alpine binding, and the system is less suitable for hard-charging resort skiing or for skiers above roughly 90 kilos in technical terrain.
For the international topptur visitor, tech bindings are the standard rental equipment in the Lyngen Alps and the Sunnmøre peaks. The technique transition from alpine to tech is straightforward - most skiers adapt within the first morning - and the weight saving on the climb is substantial.