Fed question#1, choke up device

[Little Jimmy]

Local meeting discussion. Bats are checked before game. All are fine. Somewhere in the game, a batter approaches the plate with a choke up device on the bat. Is it an altered bat? Some at our local meeting said it was, but the altered bat definition speaks of a structural change. The structure of the bat wasn't changed was it? Do we simply say to the batter that it can't be used? By the way, Fed website shows 1-5-2A with choke up device mentioned in last sentence. Paper rulebook doesn't mention the word choke up device in 1-5-2A.