American bridle.

It's called western bridle it used for American-style western riding, this bridle usually does not have a noseband. Many western bridles also lack browbands, sometimes replaced by a "one ear" (variations called "split ear," "shaped ear," and "slip ear") design where a small strap encircles one or both ears to provide extra security to keep the bridle on. Some horse show styles do not have a throatlatch, most working styles do.

The letter is in the reverse of the card:

"How do you like this horse

I should like do how it to

Go for a dream love to all.

From E. Mos."