Kartech 50mm are 1030mm in length with the exception of the Kartech MS (Medium Short), which is 1000mm in length.  All 50mm axles now come with 3 pegged keyways (different from item picture) which allow use of both the 1AXK50P and 1AXK50P3 axle keys.

Uses 1AXK50P (2 peg) and 1AXK50P3 (3 peg) axle keys