because allkpop summarizes it nicely,
The trio aims to provide fresh music through the perfect harmonization of their voices combined with a cute and sexy image. The MV for their title track, “Don’t Let Go,” which is a cover of En Vogue’s 1996 hit single, “Don’t Let Go (Love)” from the ‘Set It Off’ OST (soundtrack) was recently released.
Don't Let go
There'll You'll Be (Faith Hill Cover by Lucy)
On the Road (Navi cover by Kani)
These girls have great vocals. I'm not sure if they'll last in the industry, but I'll be looking forward to what they produce in the future.