DPE's range of 40mm axles are the most common choice on Australian tracks. Going from "Hard" right down to "Extreme Soft" in 3mm wall, and a 2mm offering as well if you want to go REALLY soft. A great product, and Australian made.
With the exception of the 2mm thinwall axle, they use standard 8x5mm keys with most European hubs, and 8x6 with DPE hubs. The 2mm axle uses this key