Dew heater with 20 cm strap is designed to fit 2” eyepiece, guidescope or finderscope. Works with 12V power supply and produces 4W of power. Equipped with standard RCA plug for compatibility with popular controllers. Comes with 2m silicone cable. The strong velco strap makes it easy to wrap it around your telescope and hold it in place. Note! The OTA size is only estimated. Please check your OTA circumference before buying.