Many Android Wear devices have optical HR (although accuracy is usually low).
There's also the Adidas Smart Run, TomTom Cardio, and Mio Fuse/Alpha 2 on the sports world size. (they all use a Mio sensor AFAIK)
These are just the standalone optical HR sensor devices off the top of my head, there are tons of ANT+/BT Smart accessory devices.
Many Android Wear devices have optical HR (although accuracy is usually low).
There's also the Adidas Smart Run, TomTom Cardio, and Mio Fuse/Alpha 2 on the sports world size. (they all use a Mio sensor AFAIK)
These are just the standalone optical HR sensor devices off the top of my head, there are tons of ANT+/BT Smart accessory devices.