Pair of 2.4mm holes pre-drilled.
This wheels can also mounted on the Losi 22 by converting front axle with Losi's SC front axle Part# TLR1108
and clamp a Losi SCTE Hex.as a 2nd picture showing below. (Thanks John Themelis!)
Made out of perfect mixture of nylon and plastic to keep it true spinning, while staying in single piece after that huge jumps!