SIGMA ENGINEERED SOLUTIONS ProConnex 41309 Ground Clamp 1/2" - 1" 1 Count (Pack of 1) auspowers_batchthree you can adjust the grind

you can adjust the grind grade in them from coarse to fine by twisting top nut

jams or alcohol

Model: GG0B

And it's designed to use it for long time

SIGMA ENGINEERED SOLUTIONS ProConnex 41309 Ground Clamp 1/2" - 1" 1 Count (Pack of 1) auspowers_batchthree you can adjust the grindSIGMA ENGINEERED SOLUTIONS ProConnex 41309 Ground Clamp 1 2" 1" Sigma Electric ProConnex 41309 Ground Clamp 1 2 to 1 Inch, 1 Pack Product Features Connects bare wire to copper or steel water pipe or tubing For pipe or copper rod sizes 1 2 in thru 1 in, wire range #10 #2, and rebar range 5 8 in thru 3 4 in Copper alloy construction with zinc plated steel screws Product is UL and CSA listed