Nice and small, reasonably long coax lead. I cut the lead to the internal antenna on the HC-05 board and soldered this on to get the signal outside the metal project box. Not certain I had to do this but . . . Seems to work fine in the house where I'm using my project. I added the HC-05 to an Arduino shield and had to add a relay for the TX/RX signals in order to program the Arduino (an issue with the HC-05 not the antenna).The only issue I have had is tightening the antenna so it remains in one position but where it is on the back panel seems to work fine (with the phone app I built).
Rating: [5 of 5 Stars!]