517eb1a1_Toppers___BedBathandBeyond_com__What_it_s_for
[Mattress Topper Type] Fitted Mattress Pads [What it's for] 
A fitted mattress pad works like a fitted sheet-a ring of elastic around its bottom edge helps secure it to the bed. Unlike a sheet, however, a fitted mattress pad is quilted on top to provide a comfortable sleeping surface-and to circulate air to help sleepers' body temperatures stay more even during the night. Fitted mattress pads are a good match for most standard-size mattresses.
Buying Guide to Mattress Pads & Toppers - BedBathandBeyond.com
What it's for