A small allen tool 2,5mm 3mm & 4mm

thingiverse

This is a small handle for allen keys that makes screwing and unscrewing a breeze. To finish the job, use a standard allen key. Cut the key to 17mm in length and insert it while the piece is still warm. Gently tap with a hammer to secure it in place. If the allen key doesn't stay fixed, apply loctite. Print Settings: Printer: CTC i3 Pro B Rafts: No Supports: No Resolution: 0.1 Infill: 100%