PIN texturization refers to texturing by a magnetic spindle, the PIN (hence the name). With PIN texturization, the yarn drives around the PIN that is rotating. This creates a twist on the yarn (which effectively comes into shape when leaving the tension-reduced exit) which is later on heat set in a heater.
The advantage of PIN texturization is the ability to work with very sensitive yarns. Furthermore, PIN texturization leads to the biggest elasticity possible (compared to other texturization techniques).