XS/SM is a perfect fit (i normally wear small)
bought this to replace the original strap that came with my FT40.  XS/SM is a perfect fit (i normally wear small). it took quite a bit of pulling to get the transmitter to attach --snaps were just a tad too close together (hence the 1 star deduction). could be difficult to get transmitter off again when washing. still a good buy for $12.50. I've worn thus 3 times now and it stays on well.
Rating: 4 stars