The MFJ-1715S is the SMA connector version of the MFJ-1715.
12 ½ radiator is a ½ wave on 440 MHz -- gives hearty 2.15 dBi gain. On 2 Meters get an efficient loaded ¼ wave antenna.
The MFJ-1715S SuperFLEX ThinDuck can be bent, twisted, flexed, and tugged, and it will bounce back into shape.
The smaller MFJ-1713S is also available.