Mouth Ring Gag

: Health & Household - Amazon.com

The straps adjust to fit most sizes, pulling the tight and keeping the open wide. O Diameter 1.9 inches. One size fits most.

- Etsy

Christmas gift/ BDSM open with Tongue Depressor Leather & Steel fetish bondage by Handcrafted/ Adjustable O-type (7). $56.39. FREE 

YELO Open Restraints, Head - Amazon.com

Buy YELO Open Restraints, Head Harness Restraint Oral Fixation, Adjustable Strap: & Muzzles - Amazon.com ✓ FREE 

O - Etsy

Open bdsm open bondage fetish silicone slave submissive

Review: Open Your and SayNothing | Elia

Open-Mouth keep the open, usually in kink play for purposes of oral sex. Spider and (like the one in this review) 

What's the standard diameter of : r/BDSMcommunity

The absolute largest I've found is 2.6" diameter. usually cannot be used to penetrate with. They simply can't unless you have a HUGE 

Hollow Two | Shires Equestrian Inc

A hollow makes this bit lighter and softer whilst the two offers leverage options to increase severity. The 5" and smaller sizes of this bit 

Centaur EcoPure Soft Jointed Loop Bit

Check out this fantastic Centaur EcoPure Soft Jointed Loop Bits and more EcoPure horse bits at Equus Now.

Suggestions for making custom open

Scale it up with an offset for the two claws to size for a human jaw as well as add pads that catch onto the teeth and have it force the

Centaur EcoPure Soft French Link 2

This Centaur EcoPure Soft French Link 2 is rubber coated and softer on the horses