This is an adapter for the Tune Trapper Hidden Antenna (P/N 853). This adapter is required for Harley-Davidson® '14-'19 Electra Glides, Road Glides, Street Glides & Tri Glide.
 
P/N - Description & Fitment
867    
Tune Trapper Hidden Antenna Adapter for '14-'19 Touring
Harley: '14-'19 Electra Glides, Road Glides, Street Glides & Tri Glide