The PTO shaft spider is a key mechanical component in the driveline that allows for a flexible connection between the tractor's drive shaft and the agricultural machine's shaft. The spider acts as a joint that allows for power transmission at different angles, which is necessary when the shafts are not perfectly aligned in a straight line. In this way, the PTO shaft spider allows for compensation for differences in the position and movement of the machines when working on uneven terrain.

The spiders are usually made of strong materials such as steel to withstand high loads and varying operating conditions. They consist of four arms that connect two drive shafts using needle bearings, allowing for free rotation and minimizing friction. Regular maintenance and lubrication of the spider is crucial to ensuring its longevity and reliability, as it is one of the most stressed components in the drivetrain.