Are rings and pickup shoes legal? When used to transfer electric current.
Are you referrring to “slip rings”? If so they are only legal if purchased as a completed part and are less than the $200 per part limit. OR You may manufacture a set if you can find materials that meet the flow chart on p.14. The inspectors will be interested to check on the safety of said device at all inspections, which may require some special investigation. Otherwise there have been slip rings on robots in the past.
However, FIRST frequently makes changes based on experience from previous competitions. To be safe, post the question on the Q & A. Slip rings had been banned in the past as well.