The Movix Tracker, used with SlimeVR, is not affected by magnets or metal interference, and it doesn't lose the position of your legs because it uses sensors that only measure the rotation of your movements. Over time, a small error in direction (called "drift") can occur, making your body appear to be slightly turned in the wrong direction. But this takes a long time to happen and is easy to fix: just stand up straight and press a button to recalibrate.