Replacement Motorola RDU4100 Two-Way Radio Shoulder Speaker Microphone - Handheld Push-To-Talk (PTT) Mic For Motorola RDU4100 Replacement Motorola RDU4100 Two-Way Radio Shoulder Speaker PTT Microphone Kevlar reinforced coiled cable plus cable strain relief for maximum durability Receive and transmit clear audio quality in any type of environment without having to pick up your radio Ergonomic and easy to grip design with a large PTT push to talk button for convenient operation Wide 360 degree rotating clip attaches onto a shirt or collar securely. UpStart Battery Brand. On Sale for a Limited Time!