You can choose whatever sizes you prefer, only pay attention to the different weight limits. If a box or item is overweight, it will be repacked into two boxes. Boxes size available:

Small (For books and other small items) 50x30x35cm / 19.65×11.80×13.75in / max 30kg / 65lb

Medium (For Kitchen utensils and small items) 60x40x35cm / 23.60×15.70×13.75in / max 25kg / 55lb

Large (Only for clothing, bed linens and towels) 40x35x70cm / 15.70×13.75×13.75in / max 20kg / 44lb