These are the standard frames for all Wildtrek and Ultrahike rucksacks. Please refer to the size chart below for the frame size of rucksack.

RF-01 = Wildtrek 55 size W1
RF-02 = Wildtrek 55 size W2
RF-03 = Wildtrek 60 & 70, Ultrahike 60 size M2
RF-04 = Wildtrek 60 & 70, Ultrahike 60 size M3