You have successfully added from to your part list.
These are set screw type ball rollers with spring plunger function.
Their internal springs receive loads evenly even when the load is unbalanced.
These rollers can also be used as a general spring plunger with ball for fixing and locating workpiece. The smooth rotation of the ball reduces friction between the main ball and receiving side.
BRPSS-S ----All Stainless Steel
BRPSS-N ----Main Ball：Polyacetal
These ball rollers have drain holes and are intended for food production lines and other applications that require cleaning.