"Advanced marksman training gives the soldier’s rounds a greater Suppressive effect on his targets. "
— Battlelog description
SUPR is a specialization in Battlefield 3. It increases the effect of Suppressive Fire on targeted players. It counters and is countered by the COVR specialization. This specialization is a good choice for the support class because it noticeably decreases the time for suppression to take effect.
The specialization increases the suppression effect dealt by 50%. The solo specialization is unlocked at rank 17, while the squad variant, SQD SUPR, is awarded at rank 33.