Plastic fingerpick with shell print creates a warm, tonal response and increased control. One might think it is worn as a claw, but it's turned 180 degrees around.
 
Fingerpicks are often used to play bluegrass style on banjo, but can be used on most stringed instruments as well.
 
While picks come in different sizes to better fit your finger, they also come in different thicknesses and materials (plastic and metal). The type of finger pick you choose largely depends on your experience level and style of music.