I looked at all the options (I could find) to add a GPS tracker to my P2/Zen/GoPro and settled on the Tagg PetTracker pettracker.com. Looks like the weight is a bit over 30 grams, and the size is about 1.5" x 3.25" x .75" (some of that size/weight may be removable with out cutting into the case. Dont know till I get my hands on it). What I liked about the Tagg is that its self contained, has its own rechargeable battery, is water resistant, GPS based with cell service in most areas I'd be using it with. There is an $8/month service fee which is not so nice, but the alternative for cell based systems would be to get a SIM card adapter for my phone, or get the Tagg its own line, which would be at least another $8/month. I just started doing some FPV flying, and am sending my P2 beyond where I can easily find it if I go out of control range or if some system failure causes a crash. I figure $100 + the service fee is reasonable consider how much I've got tied up in the flight end now. In any event, I ordered it from Amazon and expect it tomorrow. Would like folks who use the Tagg to relate some of their experiences with it and also to post pictures of how they mounted it. I know this has been covered in previous threads, but this is a popular enough subject that I cant see the harm in bringing it up again. I know lots of folks use the TK102, and while I considered that one, I decided I like the form factor of the Tagg. Its from Amazon, so if I dont like it I can send it back and won't have to pay the service charge since the first 2 (or maybe 3) months are free. I'm also going to post a thread in the P2 Non Vision forum about weight of add ons (when I'm done I'll have the Tagg, mini IOSD, Immersion Tx and Groundstation Air Unit which probably add close to 100 g of weight including wiring) for anyone who wants to comment on that.