From Twister Sisters Designs

Create pinwheels by simply sewing squares together!
This fun little twister size is perfect for 5in charm squares or cut up your stash into 5” squares. 
Tool measures 3-1/2in square and makes 6in finished pinwheels.
Includes table topper pattern.
Durable thick acrylic with raised feet for easy placement and no slipping.
Other available sizes include Midi Twister for 6-1/2in squares & Twister for 10in squares.
Works with many Quilt Moments patterns, Around the Bobbin patterns, and Let’s Twist book series, plus many more twister friendly patterns on the market.