HSR or High Speed Response is a function of the radio and reciever and not the servo. I know that KO Helios and the new Futaba 3PK have it but don't know about others. This is also the same as fast frame rate. The faster rate gives you faster servo response times and even faster than the listed numbers. It is kind of like a turbo for your servos. Beware though, as this only works with digital servos. If you try to use it with analog servos they will burn up and so will your receiver.