Suet feeders come in a variety of shapes and sizes.  Some are  hopper style feeders that have suet on both ends some are upside down hanger types so the clingers can hang below them while they eat.  These suet feeders attract a wide variety of birds, downey and pileated woodpeckers, blue/scrub/mountain jays and others. The common ingredient is the suet feed that attracts such a wide variety of birds.  

Suet is a mixture of fruit, seed, peanut butter and other grains as well as mealworms can be processed to form a cake that acts as a high source of protein and energy for many bird species. Hot pepper suet can be used to deter the mice and squirrels.