All rollers should be banded to allow for good record keeping. This allows the breeder to know which parents are producing their top birds, age of the birds and relatives. The more notes you keep on each bird the better your knowledge of the birds will be.
The bands besides having an identification number should also have the year they are hatched. Some breeders like to have a personalized band that has their name or loft name plus a number and year on their bands. Others like using a club band.
Rollers should have either a 7 mm, 7.5 mm or 8 mm size band. Remembering that the smallest needs to be put on the squab at the earliest time (7 days) , while the largest can be put on at an older age.
Bands can be purchased in a plastic coated aluminum core, plastic coated plastic core , or aluminum metal bands. There are assorted colors that change from year to year that help the breeder distinguish different years at a glance. If showing or flying competitively then your birds will need to have seamless bands. If showing National Pigeon Association shows then they must have NPA bands. To fly any NBRC flies they just need the seamless bands on them.