The XCortech X3200 Mk3 Shooting Chrony is one of the best and most reliable FPS testers available.
This chrono measures FPS values from 90 FPS to 1200 FPS and can also measure Joule values from 0.01 to 999 Joules. Furthermore, this chrono can handle a maximum ROF (Rate of Fire) of 5000, which is considered very high.
This Chrono can be powered via a Micro USB cable, but please note that despite this option, it has no charging function and therefore cannot charge batteries. It can also run on 2x AA batteries, but unfortunately, these are not included with this Chrono... this also applies to the micro USB cable.
On the bottom of this chrono, there is a mount for attaching it to a tripod. It weighs 200g and has dimensions of: 113mm x 97mm x 55mm.