It does what it says on the tin. (for non-UK folk, that means the clue is in the title). 

The Bumsaver 2 is packed with extra protection and increased coverage, all in a slim, unisex profile. Our unique dual zone foam provides increased impact absorption with less bulk. Gapless coverage protects sensitive hip, sit bone and tailbone areas. Mid-thigh length and tailored profile fit easily under pants. Flexible and form-fitting design allows for greater range of motion. 

CE compliant with Personal Protective Equipment Regulation (EU) 2016/425. Tested and certified to PPETS0002 based on EN 1621-1:2012.