This listing is for a QEP Universal Mixing paddle with the following dimensions:

Length -  16" long 
Head diameter - 3-1/4"
Shaft - 3/8"

The optimal mixing tool for small volumes of thinsets, mortars, cement, plaster & similar viscous materials
The shaft fits standard 3/8" and 1/2" drill chucks
The special shape and design takes the stress and high torque off the drill making it excellent for cordless drills.