3990-95-4
Crowley Tool 3990-95-4 Insert MRO129608 (Pack of 10)
A nice upgrade with the 7000-1GAL is the built-in handle that doesn't wobble.
Crowley Tool 3990-95-4 Insert X119170209 SHV (Pack of 10)
You will find that the alloy steel rail system glides without any sticking points.