UGears Harry Potter Advent Calendar Model Kit. UGEARS. Step into the magical world of Harry Potter this holiday season with the UGears Harry Potter Advent Calendar Model Kit! Each day you will discover a new surprise to build, from iconic Harry Potter items like the Golden Snitch and Harry's Spellbook, to other character figurines! The excitement and anticipation will build as you open the first of 24 windows to reveal an enchanting world of wooden parts and instructions.