In medical contexts, these are spherical, clear plastic bags with a sewn-in elastic band around the opening. 

• Purpose: Used as sterile barriers to protect large equipment like X-ray devices, surgical lights, and image intensifiers from fluids and contaminants.

• Design: Often called "shower-cap style" due to the elasticated edge that provides a quick, snug fit over irregular shapes

• Customized with specific thicknesses (50–100 mic), colored, printed and sizes