"My ferrets aren't happy about any harness (are any ever?), but they seem to find this one more comfortable and secure than any others I've tried so far. I recommend taking the bell off before introducing your ferret to this jacket, however. The jangling behind their heads seemed to bother my guys as much as the jacket itself.
Main downside is that the jacket itself is rather shoddy--lots of loose threads, irregular zigzag stitching, etc. It doesn't bother the ferrets but it did bug me."