We were told by our paediatrician not to use ANY kind of cot bumpers they aren’t necessary and children can get caught in them. They also affect the airflow through the cot. I’ve never used them for this reason. This advice is only a few months old BTW.
Not sure where to post this but I know cot bumpers that tie aren’t safe but didn’t know if these are any better? They Velcro.. Here’s a link to what I mean http://www.dunelm.com/product/sweet-dreams-pack-of-8-bumper-bars-1000085329