I've owned both the original XLR-K1M which I eventually sold to buy this revised model XLR-K2M. I use them with my AX100 and A7S. They both work great, they are pricey but they are worth it to me for their simplicity as they don't need their own battery and they integrate with the camera nicely. They are a no brainer to me, but as always everyones needs vary.