The use of elastic yarns in knitting presents challenges to machinery manufacturers. Some of these challenges can be solved by elastic yarn feed mechanisms, such as the SENSO-TEN F2000 positive yarn feed device, which uses sophisticated technology based on the Roser system. The elastic yarn packape is suspended above the head height, and the yarn runs through the tension control device to the package located behind the cover. The commutatorless DC motor and sophisticated electronic sensors control the speed and acceleration of the elastic yarn, monitor yarn tension, and maintain constant yarn tension. The potentiometer allows yarn tensions to be adjusted within a range of 10 grams. When the yarn breaks or is distorted, the package stops immediately and the hosiery knitting machine is switched off.