Skilled Riders

Use this Stratagem in your Movement Phase.
Select one ADEPTUS ASTARTES BIKER unit
or ADEPTUS ASTARTES LAND SPEEDER
unit from your army. If that unit moves that
phase, then models in that unit have a 4+
invulnerable save against attacks made with
ranged weapons until the start of your next
Movement phase. If that unit Advances that
phase, models in that unit instead have a 3+
invulnerable save against attacks made with
ranged weapons until the start of your next
Movement phase