Looking to get a few of the plastic nut caps on the locking collar that prevents them from loosening. Can't find a mention on their site about the Manfrotto 3401 (need the name of the part so I can search). I have the newer model Manfrotto 3021 BPRO and it doesn't utilize the same plastic caps. So it's specific to the older models but am having no luck finding info. Any help would be appreciated.