I was skeptical of whether or not I'd really like these, but they dressed up my rack dramatically, and now I don't need to worry about either hurting myself or damaging something by inadvertently hitting a bolt head. They are made of a somewhat flexible material, so they are somewhat soft rather than hard. They fit snugly and sometimes require something like a butter knife to pry off a bolt head (which is good, or they'd be falling off all the time).