SpyderX uses a design where the lens cap is the counterweight. Once the cap is snapped off the optical system of the Spyder, it can be slid up the cable to serve as a counterweight when hanging the Spyder on your screen. The USB cable runs through this cap and can be slid up the cable. If the cap seems tight on the cable, pull it gently the first few times until it loosens on the cable. Note: do not hold the SpyderX and pull the lens cap to slide it along the cable. Instead, grip the cable where the it attaches to the SpyderX to adjust the lens cap along the cable.