<p>I am using Dawn Tech GPS, which is number 4 I have used and by far the best. I admid, I have never used Nikons own due to price. The Dawn Tech is fit to my D810 on a permanent basis, and only occasionally moved to my D700. The only "problem" I have had, is that the first abt. 10 photos I took one day all had the GPS position of the last photo taking the previous time I used it. I simply started to early e.i. before it got the new satellite connections. Now I switch the camera on in the morning before leaving my accomodation, as it does not use a lot of power.</p>