To embroider on Santa Hats, Stockings and Shirt Cuffs I would recommend our Small Compact Back of Cap, not this large one. Hoop Tech.

Large back of hat clamp. This Easy to use back of hat clamp attaches to your cap frame driver and has the following inside dimensions: 5.5” x 2.875”

It will work with your existing cap hooping gauge and your machines driver. The optional small version of this clamp has 5.5” x 2.5” dimensions.

See Justin from Hoop Tech talk about cap frames at the Houston Virtual Quilt Festival!
Specifications
Features Include
(2) Backing holding clips to secure packing while framing up the cap.
Mounts to machine using existing cap driver.
Single lever opens, closes and locks the clamp.
All stainless steel metal construction for many years of service.
Fully adjustable clamp adjusts to different fabric thickness.
Clamping action does not leave “hoop burns”
Use your existing Tajima framing gage OR existing Barudan framing gage with HTP adapter piece OR the HTP Framing Gage with the patented T-bar stretcher (all machine types).
Even “Flex Fit” Made Easy
The Clamp for Cap Backs makes short work of the challenging Flex Fit caps. The elastic fabric and sweat band are easily clamped and adjusted for a smith, tight hold. Making embroidery on the back of caps quick and easy.
Other Images

icon Optional small compact frame is on the left. Large back of cap frame is on the right. lamp for Cap Backs is the easiest and fastest way to frame up a cap back. The extra large sewing field with locating points for centering, makes it easy to sew low across the cutout or high on the cap crown for those large design requests.