Retekess TR503 FM Tour Guide System Wireless Microphone Translation Service Pager 10-Year Guarantee: Astronomik offers a

10-Year Guarantee: Astronomik offers a 10-year guarantee on all filters

Cooling up to 35°C below ambient temperature

DSLR photography (astro modified): Good

Touch keys on the control panel to set up the length of how long the LED indicators

Retekess TR503 FM Tour Guide System Wireless Microphone Translation Service Pager 10-Year Guarantee: Astronomik offers aRetekess TR503 FM Tour Guide System Wireless Microphone Translation TR503 Tour Guide System Support Limitless Radio Receivers FM Transmitter FM transmitter The transmit frequency of this wireless microphone adjustable from 87MHz to 108MHz. 30 meters transmission distance in the open air. High sensitivity microphone Hands free and 16 levels of volume adjustable Rechargeable battery Built in rechargeable lithium battery, about 8 hours of continuous use.