Surely you know both the Mighty Flea is like the Big Deal, the two smallest Yo-Yos in the world, one with Hubstacks and one without, and even all its components are sized "mini".
With these two charismatic Yo-Yos, special strings used exclusively for this model. It is a string type 4 thickness, I.E. 2x2 threads and made of 100% polyester. Besides being thinner, the string is also shorter, approximately 70 cm.