This is a fixed axle (no bearing) heart shaped yoyo. It has been designed to be printable in one piece with no assembly required, just need a yoyo string. 

The button holes while cute, also serve a purpose as the yoyo's response system (what makes it go back up the string when you tug)

Recommended to print it in as thin a layer lines as possible (.05, .07 etc) in order to not wear down strings and have best playability. Ideal weight varies person to person but I found 6 perimeters, 6 top, 6 bottom 15% infill came out to 54 grams, which is a solid weight for a fixed axle yoyo.