Shield Release Recovery Time - this rates how much of a lag there is after you release the shield button (R, L, and sometimes Z).

Group A
---14 frames recovery time
---3 characters: Jigglypuff / Peach / Zelda

Group B
---15 frames recovery time
---14 characters: DK / Dr. Mario / Falco / Fox / Ice Climbers / Kirby / Link / Luigi / Mario / Ness / Pichu / Pikachu / Sheik / Young Link

Group C
---16 frames recovery time
---8 characters: Bowser / Captain Falcon / Ganondorf / Marth / Mewtwo / Mr. Game & Watch / Roy / Samus

Group D
---17 frames recovery time
---1 character: Yoshi