Halifax power-poppers from the Sloan galaxy — not only did the Nova Scotia stars provide the young quartet with a label, they furnished a fill-in drummer for several tours — the Super Friendz bring sparkling tunefulness and invention to the unpretentiously delightful Mock Up, Scale Down. Informed both musically and topographically by the environment of their maritime city, Super Friendz draw romantic conundrums in watery colors (“Undertow”), hit the beach in “Come Clean,” fall overboard on the Beatlesy “One Day” and explore paradoxical provincialism in the rock-idol entreaty of “Rescue Us From Boredom,” an energetic rock wave amid the album’s brisk breezes. Adjusting their instrumental roles for each song, guitarists Matt Murphy and Drew Yamada and bassist Charles Austin (like Yamada, a Toronto émigré) share the vocals in high, fresh voices, providing variety and fleshing out a more complex personality than most such bands can offer.