This red ball gag harness uses a gummy gag which fills the mouth well and keeps them quiet.

For those not requiring locking buckles, then these standard d-rings will do the trick. Just cinch them down to get a nice tight fit. To make this gag your own personal device you can trim the excess leather ends, if any since plenty of strap is provided to fit all heads. Secures under the chin with a buckle style strap and around the top and back with the d-ring style buckle. Value priced. Ball gag diameter is a reasonable 1.5".