The EX10 were done in two different versions from Steve Ku. In the first run he did the EX10 Fatty and in the 2nd run a EX10 that was looking like the original one.
EX10 and D10 side by side
D10 (2nd run) and EX10 Tritium Slots View
EX10 "Fatty" surrounded by two LF2XT BeCu
There is also, if I remember correctly a Russtang EX10 done some time earlier than the Steve Ku versions. I guess there are not that much Piston Drive Lights out. From what I know this Technology is owned by McGizmo and was licensed to Nitecore.