I am lucky enough to get my hands on a Realistic TRC-86, the walkie talkie they used in the series. Not sure if it works but just to have as display is
Pablo Gimenez - Stranger Things Realistic TRC-180 Lucas' walkie talkie.
Vintage Realistic TRC-201 Walkie Talkie 2 Watt 3 Channel, With Boxes, 1070's, 10 B31-6-26 - Etsy UK
Realistic Brand Walkie Talkies, 6 Channel Citizens Band Transceiver, Never Used, Portable Two Way Radio, 5 Watt, 1990, TRC 220 - Etsy | Walkie talkie, Two way radio, Citizen band
Realistic TRC-226 Portable 40-Channel Walkie Talkie/Citizens Band Transceiver | eBay