Motorola NAF5084, NAF5084A Flexible Whip Dual Band 700/800 MHz Quarterwave Stubby Radio Antenna
This is the same as 8505241U15.
Flexible whip antennas have a one-piece finish and steel core for optimal radiation characteristics. Provides more comfort when radio is worn on the belt.
Length is about 3 inches, usually called the short "stubby" antenna
Compatible with XTS5000, XTS3500, XTS3000, XTS2500, XTS1500, MT1500, MTS2000, PR1500, SABER