This listing is for a

Cotswoldsport Roller Curb Gag

Bit size as heading

Mouth piece is a 16mm diameter  
Lozenge overall length 46mm with 11mm dia rollers
Lagrge Ring Size 85mm 
Small rings 30mm
Shank length 120mm
200mm black nylon cord each side with brown leather curb 130mm
 
 
All dimensions are approximate

This is a curb gag made with a stainless steel mouthpiece, featuring a dog bone link with german silver roller pacifiers.

https://www.cotswoldsport.co.uk/Main-Shop/pics/e/csbits/Roller_Curb_gag2.jpg

The mouthpiece is designed to give the busy mouthed horse something to play with, which can also help with a horse that fixes on the bit. The copper aids salivation and acceptance, but is only mild to prevent over frothing.

Curb gags are relatively new to market, but have been used by many top riders including Ellen Whitaker and William Fox-Pitt.

The curb gag has a sliding rope you attach reins to to apply pressure to the horse's curb groove via the leather pad, with minimal poll pressure. This is a milder action than most mechanical gags and is ideal for horses who react violently to stronger bits.

https://www.cotswoldsport.co.uk/Main-Shop/pics/e/csbits/Roller_Curb_gag1.jpg

Ideally this bit should be used with two reins, but can be used with one, roundings or split reins.

This bit has stainless steel cheeks and mouthpiece. The mouthpiece is 13mm.