What is a halal pension?

Could you please elaborate on the concept of a "halal pension"? I'm interested in understanding how it differs from traditional pension plans, and what specific criteria or principles make it considered "halal" within Islamic finance? Is it designed to cater to the unique financial needs and beliefs of Muslims, and if so, how does it achieve this? Additionally, what are some of the benefits or advantages of investing in a halal pension compared to other types of retirement savings options?