Besides the logo, it looks like there’s almost no difference, inside or out, between the Sig Sauer Mosquito and the GSG Firefly.
After buying the GSG Firefly for about $218 (the Mosquito is going for about $400 at the time of this writing), NicTaylor00 shoots it and takes it apart for us, talking through his full review, side by side with the Sig.
What we learn is that the Firefly is truly a clone of the Mosquito in nearly every way, including cross-compatibility with Mosquito mags, including the base pads and +4 followers gives you a total capacity of 16 +1.
In Nic’s own words: “I don’t really know what else to say, except that it’s a mosquito!”
That said, the Firefly has the same advantages—and disadvantages—as the Mosquito, so larger-handed buyers beware. While something like the GSG Firefly might feel comfortable to hold at the counter, it may be wise to see if you can find a good place to rent one before you buy.
Time will tell whether the Firefly comes to replace the Mosquito as the favorite .22 LR selection for younger or smaller-framed shooters.