Deeper than slotted so that full thread engagement is not compromised by the slots.
In addition, the cotter pin head and split ends will be less proud when spread.
Usually machined and with a washer face.
Available in Bright Steel Finish in
Imperial UNC :- 3/8″ to 2″, UNF :- 1/2″ to 2″
Metric Coarse M12 to M24, Metric Fine M12 to M30