These are pocket knives with blades that can be folded/opened (even multiple times 🙂 ). They are typically made with various locking mechanisms (slip-joint, traditional spring, cross lock (liner-lock), friction lock, etc.). They enable easier carrying and simpler wearing. In terms of their use, they are generally designed for everyday work (Every Day Carry), but one or two types, especially thanks to their more massive construction, are also suitable for bushcraft-outdoor purposes. Compared to fixed-blade knives, they have a more complex structure, thus their production also takes more time.
Palcsesz 'Angelero' Imre