Bits are Not Returnable - please be sure you order the correct size

This Stainless Steel bit by Weaver Leather has a Medium Port and Copper Mouth. Picture shows it as black steel but it is shinny Stainless Steel.

WEAVER LEATHER features a full selection of Riding and Driving Bits:
BP - Brass Plated
BS - Black Steel
CO - Copper
CP - Chrome Plated
MI - Malleable Iron
NP - Nickel Plated
SB - Solid Brass
SS - Stainless Steel
ST - Steel

Curb bits are leverage bits that are generally used when riding with one hand. They work on the bars of the mouth, under the chin when using a curb strap or curb chain, and over the poll. Curb bits are available with many different shank lengths. The longer the shank, the more severe the pressure is when the reins are pulled back. At the same time, the horse will be rewarded quicker when the pressure from the reins is released. A curb bit with a shorter shank will not be as severe. However, it will also not reward the horse as quickly. Curb bits sometimes have curved shanks. This delays the signal time to the horse and is more pleasant to the horse. Curb bits have a solid ported mouthpiece that relieves the horse's tongue pressure.

How To Measure Your Horse's/Mule's Mouth For Bit Size:
Get a friend to help you do this...take a piece of string and pull it straight across the inside of the horse's mouth where the intended bit will lay. Use a marking pen to make a mark on each side where is comes out of his mouth. Measure between the two marks and add 1/2" to your measurement. This will allow 1/4" clearance on each side of his mouth for a comfortable bit.