Take a look into S01E05 : Motorola D520 part 1 - YouTube
Motorola DM4600U Mototrbo Digital Mobile (450 - 520 Mhz) – Paris Radio
Old Motorola mobile phone Stock Photo - Alamy
Motorola GP338 Portable, UHF (450 - 520 MHZ) 16 channels, 4W, with keypad Two-way Radio With Battery, Antenna, Charger, and More : Amazon.in: Electronics
Motorola DM4601 Mototrbo Digital Mobile (450-520 Mhz) – Paris Radio
Motorola D520 mobile phone | Museum of Design in Plastics