They should be called JUNK-JUNK-JUNK. You can buy 2 small levels at your local hardware store for a lot less the 1 level worked on my top turret but the other 1 was useless i paid $25 for these locally & they are plastic JUNK. "BEWARE YOU WERE WARNED"
Cons: They are JUNK.
This review was written in the old system and had content requirements that are different than reviews written today.