The TETHYS is a compact and lightweight pulley with rotating flanges and a large attachment point that accommodates two carabiners. For use with ropes up to 13 mm. Prusik minding, the self-locking knot can be installed on both sides. Self-lubricated bushings are sufficient for light applications at low speed. Efficiency: 80%. Aluminium alloy body and wheel, stainless steel axle.