A Chaplet is different from a rosary in that it's format is usually a shorter prayer form. There are Chaplets which are very short, others quite lengthy. However, there are rarely the number of meditations found with a Chaplet as you have with the Protestant rosary.

The Chaplet of Divine Mercy is an offering of the present, not the past nor the future. There is so much involved with the Chaplet of Divine Mercy that trying to go into a deeper explanation here is not feasible.

The Chaplet of Divine Mercy uses the same rosary as you use for your Protestant rosary prayers. The difference is it is a 'chaplet' meaning the same prayer offerings are repeated on all five decades around the rosary.

For more information on the Chaplet of Divine Mercy, there is a chapter on it in the book A Ladder from Earth to Heaven: The Rosary for All Christians.