A pastel pop design that sends your heart aflutter. The fluffy fur is just so cute! 
— Website description[1]
Happy Synthesizer (ハッピーシンセサイザ Happī Shinsesaiza?) is an Outfit for Megurine Luka.
Description[]
The Outfit's attire consists of a fluffy white vest, a magenta strapless top with white polka-dots, long black gloves, a dark-green skirt with white frills on the trim, and long black boots with garters. Additionally, Luka wears black headphones with fluffy, light-green earpads and an attached mic on the right pad.
Game appearances[]
The Outfit first appears in Hatsune Miku and Future Stars: Project Mirai where it can be unlocked after watching the PV for "Happy Synthesizer" and can be bought for 5000 Mirai Points. It returns in Hatsune Miku: Project Mirai 2 and Project Mirai DX where it can be unlocked by clearing the aforementioned song on any difficulty and can be bought for 5000 Mirai Points in Project Mirai 2 and 3000 Mirai Points in Project Mirai DX.