1.00” inch round  die holder.
Multiple Ratchet Drives available in1/4, 3/8, 1/2”
Made from hardened tool steel.
Every auto mechanics dream. Clean up stud threads in tight spaces. 
Especially  when working on exhaust studs on engines while still in vehicle .
Spin the bolts back on!
Dies sold separately.
Please note that die holder comes with set screw not cap screw seen in picture.