At EFA we make both the calf hair and cordovan tabs. They have a cordovan or calf hair string plate, a stiff leather palm tab, and a back plate usually of pigskin. On O-ring is used to comfortably attach to the middle finger. I like the calf hair for it's smooth release but the life is short. Our cordovan tab will last a long time. In fact you are more apt to lose it then to wear it out.
Recently we started making a version of this 3 under tab with sharkskin as the palm tab. Now we have cordovan, sharkskin, and pigskin combined favorably in a unique little tab. It's not yet on the website, but can be purchased by contacting us direct.