A row of 6 removable spikes can be added to the chastity jock -  LARGE CUP VERSION ONLY - to help prevent prolonged erections.  The spikes are at about the 4.5” point within the cup - so they do not come into contact with most submissives' cocks until an erection has begun.  A flathead screwdriver is required to add/remove the spikes. More details about the chastity jock and spikes found here.