This is an Italian made axle and is used by some European kart manufacturers as their OEM axle.
Axle uses 8x60mm 2 peg keys(#AK005) for wheel hubs. 8x8x50mm solid keys(#K509) for the brake hub and sprocket hub locations.
Diameter - 40mm
Length - 1040mm
Please specify stiffness grade: Medium or Soft
Generally speaking a Hard(stiffer) axle will transfer more weight thus increasing rear grip and a corrseponding Medium or Soft axle will transfer less weight resulting in less rear grip.