Frame bindings are considered a classic among ski touring bindings. They are similar to alpine bindings and have the usual toe and heel parts, which you step in as usual. Toe and heel are mounted on a frame which swivels in uphill mode over an axle (point of rotation) in front of the toe. With each step, the ski tourer thus lifts the frame including the automatic heel, pulls the ski uphill, while the frame at the heel lowers back down to the ski. Frame bindings are heavier than pin bindings (weight of the frame plus toe and heel), which is why you need a little more strength and endurance when climbing. In addition, the point of rotation is located a little bit in front of the toes or the tip of the boot, which makes walking a little unnatural and takes more getting used to. Nevertheless, frame bindings are still popular with downhill-oriented tourers because the power transmission from boot to ski is very direct and therefore transmits the steering impulses very well. On top, they can be used with almost any boot, while pin bindings are only compatible with genuine ski touring boots with pin inserts.
Pin bindings represent the current evolutionary stage. Two steel pins of the toe snap into special receptacles in the tip of the shoe, the so-called pin inserts. Pin toes are available in combination with different heel mechanisms: downhill-oriented alpine heels (e.g. Marker KingPin) with better power transmission, or even lighter pin heels (e.g. Marker Alpinist). Their steel spring pins lock the heel for downhill skiing. The power transmission is not so direct, but these heels are much lighter. Since with pin bindings, the toes are very close to the point of rotation and the boot tilts forward more directly, so you walk much more naturally. This saves a lot of energy, which is especially advantageous on long ski tours. To use pin bindings, however, compatible touring ski boots with pin inserts and the receptacle for the steel spring in the back are required.